Substitutions

[PTref]

I understand that if A1 is subbed out during a dead ball, he cannot be subbed back in until the ball goes live and dead again, or the coach calls a timeout.

However, if A2 is subbed in on say, after the first free throw and enters the court, can A2 be subbed back out if the second free throw is made? Does he have to play time before he can be taken OUT of the game?

Does the rule apply for players entering the court as it does for players leaving the court?

Thanks.