Opinion on Play Situation

[jearef]

A fellow official recently posed a play situation to me, and I wanted to get the opinions of the officials from this forum. Here is the play:

A1 takes a shot that results in a long rebound, which is secured by A2 at the free throw line. After securing the ball, A2 immediately heads down the lane in an attempt to score. B2 is standing in the middle of the lane with his back to A2, having erroneously assumed that A2 was about to shoot from the free throw line. A2 goes airborne and plows into and through B2, who remained facing the basket the entire time. B2 never moved prior to contact.

The question is this: Do you have a PC foul on A2? If so, how do you account for the fact that B2 never had LGP, since he was never "facing" A2? My thought is that since B2 was never "guarding" A2, the issue of LGP is inapplicable. I believe this is controlled by the fundamental which says every player is entitled to a spot on the floor provided he gets there first without illegally contacting an opponent. Thoughts?