Kicked injury stoppage

[Amesman]

Boy, did we kick an injury stoppage yesterday, I think. But want to get clear.

Defense (A) rebounds and speeds up court toward its basket. I'm the new lead. As I track the fast break, a glance tells me A5 is down back around the opponent's FT line. Partner is in the area of A5 but doesn't blow the play dead, so I figure I better keep a close eye on the action around the ball. Penetration toward the hoop stops and a loose ball results in a held ball. Seems like a fair amount of time passed.

Now partner beckons coach to tend to downed player. Apparently, he was elbowed in the throat on the rebound.

What could I have done differently? Do we kill a fast break for the injured team in this situation, or do we ever let that develop?

At first, I wasn't sure if it was just a disgruntled player who didn't get the rebound, but I wasn't close enough to know one way or another so waited on partner.