During the first fight between Drew and Trevor, the crowd outside of the ring clearly disappears and reappears between shots.
During the first fight, no explanation is really given as to how Trevor is responsible for pulling down Drew's pants. Trevor does not physically pull Drew's pants down, he merely removes Drew's karate belt, which appears to cause Drew's pants to fall. Since karate belts are worn to distinguish rank, and not as a practical way to keep the wearer's pants up, this should not have caused Drew's pants to fall. If Drew really was securing his pants with his belt, rather than with the draw strings on the pants, than that is his mistake and he is responsible for the pants falling. But it would still be unclear how Trevor, who should know that a karate belt is not supposed to be used for this purpose, would know that Drew was using the belt to keep his pants up and how Trevor would know that he could take advantage of that.