I beleive Bill was very frustrated with the lapped traffic, which Nemechek was at the time. Looked like Bill was trying to pass underneath and just did not have room to come up of the corner like he needed to.
Bill was not "punted" by Joe.
Many of the drivers were struggling with lapped traffic and the lapped drivers were struggling with the cars coming up to pass them. With the high line suddenly becoming a place to run at Martinsville I don't think the lapped cars knew quite where to go to let the faster guys past. You saw the same thng with Kurt at the end of the race.
Bill ran the high line most, if not all, day long. Guessing, I would say he wanted the high groove cleared and ended up forced to the bottom instead.