In an attempt to add a little clarity, here goes...
The play was not an all-alone lay-up that rolled off the rim and was rebounded right under the basket. It was more of a drive into traffic...and more of a floating / running type shot than a lay-up. I'd say a couple feet inside the foul line.
B1 rebounds the shot at around the foul line or just below, turns, takes a couple dribbles and is near (but not across) the division line. So, yes, it is B1 who rebounds and it is B1 who initiates the break.
It seemed like A1 took a second or two to look at me in disgust before he said, "What the..." Again, it was not yelled, but it was clearly said. I think I was still down around the foul line (of A's basket) due to the fact that A1 shocked me with his comment...I knew he was getting a T and the action would be stopped in a moment, so I was just waiting to see if the break developed...and maybe a little of less-than %100 hustle
...maybe.
IMO, the break (or at least the possibility of it) had clearly started. That's why I waited. Right or wrong, I am comfortable with that part of my action.
What I'm not as sure of is, with this type of situation, is it just T once...T once and also T the second time (continued complaining)...T once but toss out? And then, how you would treat rec ball v. high school v. college.
Sorry for the confusion on the original post. I hope this helps.