@Kynon, you can't "take the deposit", you can only make a claim through the resolution center and ask for extra person's fee, or maybe in this case charge them another double room fee.
For the rude behaviour and the break of house rules, you can only leave them a telling review to warn the next host. Please do that.
You have 48h to make a claim through the resolution center - ask for the price of a room for two for a night. When they decline, press the button to involve airbnb and they will decide. If they don't answer you can involve airbnb within 72 hours, but better a bit earlier. Send them mails via the thread too.