Interesting you thought she was faking it after you wrote she went into the toilet to puke.
Regardless of the situation, ie going out in Wanchai, LKF, KTV, etc, if someone gets so shit-faced and has to go to the toilet to puke, I always tell (command is more like it) that person to go home and I also tell that person I will take care of that person's share of the expenses owed. It is worse to make the group take care of the person if person refuses to leave and it does kill the overall party mood.
Besides, I don't know about you, I don't want to be kissing a girl after she has just puked because all that upchucked stomach acids and eaten food just literally leaves a bad taste in the mouth.
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She would need some heavy gargling of industrial-strength mouthwash to clean her mouth out.
Ah yes, your group is not as tight as you would like as it seems it is more of every guy for himself.