They built a shack, placed Adam's still inside, and plugged the condenser outlet to simulate a clog in the tubing that would allow pressure to build up. The still was loaded with pure ethanol and heated; there was no explosion after 30 minutes, but Adam and Jamie observed large quantities of smoke and flames coming from the shed. They found that the still had been destroyed by fire, and Adam theorized that gradual failure of the material and welds would have let the ethanol vapor escape slowly enough to burn rather than explode.

In the workshop, they boiled a pan of ethanol inside a model shack and experimented with methods for igniting the vapor. An open flame, created by sparking a rag tucked between electrodes, caused an explosion that blew out one of the model's walls. For a second full-scale test, Jamie's still was set up in a new shack, heated, and allowed to vent its vapor until a flammable concentration had been reached. When they sparked the rag, representing a cigarette being lit by an unsuspecting moonshiner, it triggered an explosion that blew the shack apart. Adam and Jamie declared the myth confirmed.

The team used the 2010s car for the performance testing to determine whether moonshine was as effective as a gasoline replacement. They chose three different strengths of moonshine (151, 170 and 192 proof) and planned to do three trials with each strength, calculating the average time to accelerate from 0 to 60 mph (97 km/h). The car would not start on 151 proof, reached an average of 19.4 seconds at 170, and achieved 9 seconds at 192. At Petaluma Speedway, Tory drove 3 laps in this car, clocking times of 2:26 (gasoline) and 2:24 (moonshine). He noted that even though the acceleration was slower on moonshine than gas, the effect gave him better traction on the dirt surface of the track.

For the longevity test, they chose to use Thunderhill Raceway Park for the many twists and turns on its track. Grant, in a moonshine-fueled car, drove past Kari and Tory, who were standing by a parked gasoline car; they then jumped in and began chasing him. He was able to stay ahead of them through 3 laps, totaling almost 10 mi (16 km), and the team declared the myth confirmed. However, Kari commented that standard passenger car engines are not designed to run on high-purity ethanol, and that it gives poor gas mileage.

The plate glass shattered into shards that inflicted a small number of slash wounds on one analog, while the other one was not injured. The laminated glass broke into several large sheets and did not inflict any injuries; the tempered glass broke into many small fragments that caused multiple injuries to both analogs. Since the workers were at high risk of being wounded by the flying glass, Adam and Jamie classified the myth as busted.

To achieve an actual flip, they fitted an SUV with a high-pressure nitrogen cannon set to fire upward, as well as several jugs of gasoline rigged to explode. The two effects were synchronized to the impact of a dummy RPG against the front end. The cannon failed to fire on their first attempt but worked on the second, causing the SUV to flip partway backward and then drop back onto all four wheels.

Declaring the myth busted, they decided to modify the Beast so that it could successfully plow through the traffic. They fabricated an attachment similar to a locomotive cowcatcher, in the hope that it would throw the cars aside and out of the Beast's way. For this test, they set up 16 cars instead of 10 and lubricated the attachment's surface with lard; driving at 40 miles per hour (64 km/h), they were able to push all the cars far to each side and continue rolling forward.

Kari repeated the experiment, using a concentrated laboratory-grade peroxide solution and potassium iodide instead of yeast. This test generated a large volume of hot foam and steam, and was deemed unsafe for the home. In a final test, dubbed "Monster Toothpaste", the Build Team scaled up the recipe by a factor of 200. When the chemicals were mixed, they generated a massive eruption of foam.

A 2 L (70 imp fl oz; 68 US fl oz) bottle bulged out greatly before exploding and gave a maximum of 7 pounds per square inch (48 kPa), enough to cause permanent hearing damage. When Adam and Jamie repeated the test with the bottle held in a set of rubber/bone forearms made by Jamie, the blast inflicted several lacerations, fractures, and wounds from embedded shrapnel.

At an indoor facility, they set up a small enclosure (the "Cat Corral") and tried to move 8 cats into it, but neither man could get them to move as a group. Adam resorted to carrying them one by one, only to have a cat escape as he brought the last one in; Jamie worked by intimidating them, but could only move 5 into the Cat Corral. Further attempts, using only 3 cats and a combination of toys, catnip, and startling noises/movements, also failed. A final test, with all 8 cats and a sheepdog, failed when the cats became aggressive and refused to move away from the dog's advance.

The team declared the myth busted at this point, then started to design portable devices that could safely pick up and move the pigs. Kari formulated a feed mixture to use as bait and made a pair of fur-lined gloves to improve her grip; the pig ignored the bait, but she was able to easily grab and move the pig in 24 seconds. Grant's device, consisting of long-handled pincers operated by a compressed-air tank on his back, proved unwieldy and difficult to aim; he took nearly 4 minutes to complete the task. Tory attached two suction cups to a vacuum-cleaner backpack, but was unable to get a strong enough grip to hold on to the pig within 5 minutes.

Through a combination of compression and manual adjustments, they were able to squeeze a 10-pound (4.5 kg) charge of manure into Adam's bag and close it. However, the compressed material only weighed 7.5 pounds (3.4 kg), indicating that 2.5 pounds (1.1 kg) of water had been removed. Jamie considered this result to be in support of the myth, since the bag's contents no longer weighed 10 pounds.

Adam researched a method for accelerating the ball by placing it in a sealed tube, evacuating all the air, and puncturing the seal on the end behind the ball. Using a 3 ft (91 cm) tube, he found that the ball burst out the other end in excess of 300 mph (480 km/h). Increased lengths led to a higher top speed within the barrel, but caused the ball to slow down before leaving the barrel due to resistance from the air accumulating in front of the ball. However, Adam learned of a modification that involved adding a choke chamber to the far end in order to pop the seal and give the ball an extra burst of speed. With the choke in place, he and Jamie measured a speed of 779 mph (1,254 km/h) out of the barrel.

In a hangar at Fort Mason, they set up their vacuum launcher with a 150 ft (46 m) barrel and a 500 psi (3,400 kPa) air supply. Their first launch measured 1,086 mph (1,748 km/h), but the ball broke into fragments before it left the barrel; a second test, at 20 ft (6.1 m) length and 300 psi (2,100 kPa), gave 1,100 mph (1,770 km/h), left the ball intact, and allowed it to smash a hole through a ping-pong paddle. For a test of lethal potential, they fired at a slab of pork, which fell off its support hook on impact and was found to have a 1.5 in (3.8 cm) deep hole. They classified the myth as busted, noting that the wound would be serious but not fatal.

Tory built three cannon breeches out of ice, with different wall thicknesses for strength testing. When the team loaded the 8 in (20 cm) thick breech with 8 oz (230 g) of powder and set it off, the blast destroyed the breech; subsequent tests with charges up to 1.75 oz (50 g) left the breech intact, though. They then built a complete cannon and set up targets at 150 yards (140 m) in order to evaluate three criteria: range, damage potential, and reusability. Their first shot reached a speed of 200 mph (320 km/h) and covered the distance to the target zone, but did not hit any targets. A second test, with the angle adjusted to fire over the targets' heads, caused the cannon to shatter. The team judged the myth as busted, since the cannon had met only the first two of their three criteria.

To better match typical movie scenarios, in which a character might fire a pistol to hit a grenade, they switched to steel dummy grenades and paintball pistols for safety. Each man took a turn shooting while the other threw and was able to score a hit after repeated misses. For testing of live ammunition and explosives, they built a heavily armored bunker on a remote stretch of land.

A test on a standard grenade showed that the explosion would occur 5 seconds after the fuse was ignited by the spoon popping off. They set up a shotgun, pistol, and rifle to fire directly at a grenade once its fuse had been ignited. The 12-gauge buckshot round blew it to pieces and extinguished the blasting cap. The .45 pistol round knocked the cap off; it exploded harmlessly. The .308 rifle round delivered enough energy to the grenade to detonate its explosives instantly. Adam and Jamie classified the myth as plausible, but noted that a person would have a better chance of survival by taking cover due to the difficulty of making an accurate shot and the risk of setting the grenade off.

See also Jet Engine Vacuum.

Jamie then took Buster's place for a second series of jumps so that the cord could be re-calibrated for his weight. For the accuracy test, a large plastic hoop was placed in the pool; both men were able to put their heads inside it repeatedly. Finally, they placed several foam rubber apples inside the hoop, and Jamie made several jumps in an attempt to bite into them. The changing wind caused him to miss the target at first, but even after the target was re-positioned, he was still unable to bring back any apples because the ripples created by his impact pushed them out of the way.

He and Adam declared the myth busted at this point, but decided to build a device that would allow them to accomplish the feat. At the workshop, they devised a head harness with a set of mechanical jaws that operated when the wearer opened his mouth. Suspended upside down over a tub full of water and real apples, Jamie was able to snag them with this rig; at the pool, he missed the apples, but snagged the hoop on his last try.

After the show's insurance company rejected the team's plan to do their testing on a flying plane, they decided to build a set of wings, mount them on a truck's flatbed trailer, and drive it down a runway at 35 miles per hour (56 km/h). Grant's final design had a wingspan of 40 feet (12 m), and he and Tory set out to volley the ball 5 times at speed while standing on opposite ends, with Kari driving. After several failed attempts, professional tennis player Tyler Browne took Grant's place, and he and Tory were soon able to achieve volleys of up to 12 hits.

The team declared the myth confirmed, then repeated the test with Tyler and Tory standing 32 feet (9.8 m) apart, farther than their first trials. Although the increased vibrations affected their playing, they did soon attain 5 or more hits.

After modifying the cars' suspensions to make those effects permanent, they rigged a pulley system on the runway to collide them at high speed. On their first attempt, the Corvette broke free of its guide cable and the Mustang rolled off the runway and crashed through a nearby fence. On their second attempt, the cars collided and were both destroyed without replicating the movie stunt. The team then modified another pair of cars to have an even greater difference in bumper height, and reran the test. Again, both cars were destroyed by the collision, but Tory pointed out that the wreckage of the Mustang did do a barrel roll.

Having busted the original myth, the team decided to replicate the result by adding a reinforced ramp to the front of the Corvette. This time, when starting up the pulley system, the Mustang's guide cable quickly snapped and the car rolled to a stop. A successful re-test did lead to the Mustang being launched into the air intact, but it landed upside down and the Corvette was heavily damaged. The team declared the myth busted.

They focused on the tips Kari collected from the first 80 male customers on each shift. During the "small" and "medium" shifts, she collected $72 in tips, while the "large" shift yielded $98, with both men and women tipping almost 40% more. The team classified the myth as confirmed.

• Car X (Tory, weaving): 1 hour, 16 minutes
• Car 1 (Grant, leftmost lane): 1 hour, 19 minutes (4% difference)
• Car 2 (left-central lane): 1 hour, 20 minutes (5% difference)
• Car 3 (right-central lane): 1 hour, 29 minutes (17% difference)
• Car 4 (rightmost lane): 1 hour, 33 minutes (22% difference)

Jamie measured the total time needed to seat all the passengers and stow their luggage, and they rated each boarding system as "Great" (+1 point), "Okay" (0 points), or "Terrible" (-1 point). Alternatives were compared against the standard back-to-front system in terms of time and total rating points. The systems with an "outside-in" component (WILMA, WILMA Block, Reverse Pyramid) proved to be the most popular and were nearly 10 minutes faster than back-to-front, filling the seats furthest from the aisle first. The two random systems, both with and without assigned seats, were faster than back-to-front but were also the least popular.

For the accuracy and penetration tests, the team compared their ammunition against standard rounds with lead projectiles. The revolver bullets failed the accuracy test and were discarded, while the shotgun shell and bone rifle bullet gave satisfactory results. The tooth rifle bullet disintegrated before it left the barrel. In the lethality test on a block of ballistic gelatin, the shotgun shell inflicted enough shallow wounds to be judged as potentially lethal, while the bone rifle bullet did not penetrate far enough. However, when Grant made a longer bullet, the increased mass led to lethal penetration of the fragments.

Finally, the team put together human analogs from pig carcasses, filling them with simulated internal organs, and fired the shotgun shell and heavy bone rifle bullet into them from close range. When a forensic pathologist examined the wounds, she was able in each case to determine that they were caused by gunshots and to find the projectiles. Since all three ammunition types failed on at least one of the original three counts, the team declared the myth busted.