I Only Have Eyes For You - S2-E19
Revealing mistake: After Buffy has entered the wasp-filled school there's a shot of the others standing outside waiting for her. In the establishing long shot if you look closely you can see they used the same shot as earlier in the episode - Buffy is standing there with them. (00:34:10)
Answer: She has superpowers, ergo fast movement. The reason she outruns him so easily in "Touched" is that she stops trying to actually fight him and just dodges instead.
Shay