I have to agree with EllenS about the person raising a ruckus with building security. I don't know of any checkpoint that would allow someone to bully their way in or would tolerate abuse of the staff to the point where they wouldn't be ejected or arrested. The point of door security is to prevent trouble in the building, so troublemakers wouldn't be cleared to go upstairs to an interview, at least not without someone coming downstairs and clearing them in, and especially not if they never submitted to the security check.
As to the punishment levied surrounding the girls fighting, whether the punishment is "realistic" isn't as important as its place in the story. There are plenty of times when punishments are imbalanced or the victim gets worse than the bullies, so the real question is, are you trying to set up a situation where the punishment is "fair" in the reader's mind or a situation where there's an injustice to drive part of the story? If it's fair you seek, then having one of the other characters (possibly the ones levying the punishment) take her in hand to explain what happened and sympathize with her reason for fighting will make almost any reasonable punishment seem a lot more balanced. Your description of "time off with visiting rights" works well for that, as long as some character actually describes it in the story, either by telling the victim or thinking/telling someone else (although most sympathy derives from someone telling the victim so she feels better about why she was "punished").