At first I thought this was the little game on the "Highly Questionable Show" called "Si or no."
My bad.
Honestly this is a HTBT situation. I can imagine this going on with not a lot of loudness and I can imagine the coach going off. For me it would depend on how loud the coach was and what had they done previously. If it was not a T, then it certainly would be something I would probably address before or after that timeout was over. Experience is what will tell you how bad this situation is and how it should be addressed. And honestly only you will know what a line is crossed, because your line is not everyone else's line.
Peace