Revealing mistake: The shot of the two motorbikes colliding with each other and exploding into flames is very unconvincing. Watch carefully, and you can "see the join" where a shot of the two motorbikes passing each other (and NOT colliding) is replaced by a "staged" fiery explosion.
Continuity mistake: In episode 2 of "Survival", Midge is captured, and the sabre tooth he's carrying gets knocked to the ground. Neither he nor the Master pick it up before they teleport to Earth. Yet in Episode 3, the Master is able to present the sabre tooth to Midge as he's about to ride his motorbike towards the Doctor.