The seven remaining teams roll into Flagstaff, Ariz., determined to get the hang of the food truck game. Just when things start to settle down, Tyler springs a Truck Stop cooking challenge on them: Create a dish featuring the local delicacy prickly pear cactus. Celebrity Chef Beau MacMillan judges the dishes and delivers a game-changing prize -- but Tyler is not done. On Sunday, he tells the teams to go vegan, and the teams scramble again to stay above water.