Re-Shoot Free Throw

[OKREF]

Foul by B1 on shot, bucket goes. Report to table, number and 1 shot. So A1 is at free throw line. Partner bounces ball. As the shooter is about to start his shot the horn goes off, he hesitates and then shoots. Before he shoots partner starts walking up the lane upon hearing the horn, shutting it down. The table didn't get the number. So, the free throw went in, I was moving towards the table when I saw my partner moving up the lane.

So. Do we count the free throw, or shoot another one? We shot another one, as I explained to the coach, the horn sounded, your player hesitated and and partner was walking up the lane. I asked him what if he would have missed it? Would you want another free throw or just play on.