shooting foul shoots at the end of half

[readingofficial]

I had a game today where my partner call a foul as time ran out in the first half. The team was in the bonus, so the player went to the line to shoot one and one. My question is it legal for the opposing team to leave the court and go to the looker room as the player is shooting his foul shoot. We let them leave the area, but i am not sure if that is against the rules.