Sadly, what Centex says is too often true. We just don't get to practice these plays, and they happen so quickly, they are very difficult to get right on the field.
Mechanically, when the B saw the ball touched by B2, he should simply use signal 11 (legal touching), so the whole world (at least the video) knows you saw the touching. Then, from straddling the goal line, the B would see A90 bat the ball. Since he made the S11 signal, he should now know that any batting in the end zone is a foul, and he gets a flag down, and continues to officiate. He knows the ball has not come into possession, so it is still a "kick." When he see A31 recover the ball, he astutely sounds his whistle, and signals time out. Normally, the B should still let the wings take progress. But, in this unusual case, it would help to "sell" the call for the B to step over the B-2 and mark progress, until the H and/or L can relieve him, to go have that man-to-man talk with the R.
Now, you can be sure that Team A's coach is at least trying to get out to the numbers or so to make his case that this should be a TD for his team - after all, it was touched by Team B!!! That's when the U and the wing to that side intercept him and give him the one warning to get off the field. We'll let you know what's going on. Just give us a chance to find out.
When do we get to have this kind of fun again?