Not sure if you were at the game, but they made an announcement about "storming the field". While they might make this announcement for every game, it is for THEIR fans and they were prepared to enforce this rule (had they won) and they had the police to do so.
However, at this point after the game, nearly all of the UF fans had left. There were PLENTY of police officers available to secure ONE LITTLE visiting team exit. What she did was of her own volition, because she was freaking the **** out over her mistake of putting all the recruits right next to the UM tunnel.