Chael Sonnen's cry of "I didn't tap!" is a UFC in-joke. Years earlier, Sonnen yelled the same thing in protest after losing his title shot to then-champion Anderson Silva.
Chael Sonnen's quote "I didn't tap" was not originally in the script but when he had done it, Kevin James liked it so much that he kept it in the movie and awarded him with 200 dollars bonus.
During the final fight scene with Ken Dietrick the end of Round two is crowned by Dietrick throwing a Haymaker into Scott's lower jaw. This knocks out Scott's mouth guard, you see the mouth guard fly out of his mouth, and land on the wire of the octagon, in the next shot you see it still hanging on the wire. Yet Scott has to hazily walk halfway across the octagon to retrieve his mouth guard from the floor.
When Scott Voss is at the vending machine, he pulls out two packets of chips that drop, throwing one to a student who saw him. In the next shot he is seen holding two packets of chips again.