Continuity mistake: When Riley is dressing Buffy's wound, it is much further to her left side than where she was actually staked, which was more central on her stomach. (00:00:35 - 00:02:40)
Visible crew/equipment: When Spike picks up the money after Buffy has just said "you're beneath me", you can see the microphone "sender" under his leather jacket. (00:36:10)
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