Azula had no intention of taunting her captives for too long, let them waste up all their dwindling air in trying to escape. She laughed chillingly as she heard them bang against the door, using all in their power to try and escape it. But it was just a door, a very strong door. And they were injured, and they were locked in. Faith Lehane and Sam Winchester. Azula had done her research.
"Well I'd love to stay and taunt more as you seem to want me to. But its tacky. And I have things to do, and a pretty weapon the Slayer might recognise do to it with. Should I get the one that took down Kumikio next, or the older one, or the one that came back. Or his brother, or his demonic harlot"
Let them think on that.
"Oh well, I have more time to think than you do, and thinking will start to be difficult. Goodbye Faith. Remember me fondly in the time you have left."