"FLAG DOWN....oops!"

[RILAX]

This is what I would do:

First try and get a stoppage of play while team A had the ball. However since team A is on a fast break and an immediate stoppage can be more detrimental to the team than so of the other options available I would hold off the whistle. This however creates its own problems if A does not score or back out of the fast break. Once anything that can stop a slow whistle takes place the ball needs to become immediately dead. Now if the ball became dead because team B had possession of the ball or the ball became dead in the crease I would say that B would keep the ball. Also if the ball was loose or a shoot missed the goal and became dead outside of the crease I would give the ball to the team with the A.P. arrow.

Not a happy situation all around.