There is no reason why anyone should get “stuck” in the intersection. You are required to stay out of the intersection and not proceed until you see that there is enough room on the other side to cross and keep out of the intersection.
I’m usually very careful not to block the box and wait until there is room for me to go. Nonetheless, there was a time that I ended up, unwittingly, blocking the box. I was on a two lane street waiting by an intersection for a spot to clear up beyond the box for me to move up. When it did, I began to move. However, shortly after I began to move, the driver from the next lane decided he wanted that spot (since his lane wasn’t moving as quickly) and rushed forward and cut me off. By that time I was in the box and the light changed again.
But cases like that are rare. Generally speaking, there is no reason to block the box.
The Wolf