I heard an interview with him on Jason Ellis on sat radio. It was pretty cool to hear his point of view. The reason he was laying there is he was winded then once he caught his breath he did a self body check and felt good so hopped back on the bike.
Hitting that downslope saved his ass. If he'd gone a few more feet to the side he'd have been screwed...kinda like what happened to Doug Henry back in '95.