During the party at Stu's house at the end of Scream (1996), Randy ends up alone watching the movie by himself. Eventually he wanders outside and appears at the driver-side window of the news van when Gale is trying to use the cell phone (right before she finds Kenny dead).
Randy asks where everyone went which startled Gale and she hit Randy in the face with the phone and we don't see him again for a few scenes. When we do see him, he is running toward Sidney while she is trying to get back into the house. At this point, he is limping as if something is wrong with his leg.
Why is he limping? He was fine until he got hit in the face and then next time we see him he is limping.