Slytherin: starts making a list of feasible excuses for why it happened
Ravanclaw: takes a calming, deep breath, send an owl to the school, and wait doe their parents to find them so they can figure out what to do.
Hufflepuff: Isn't really worried because they know their friends will notice there missing and tell someone.
Gryffindor: Steal their dad's flying car and follow the train all the wag to Scotland. Destroying a tree that's been on the grounds since before they were been in the process, all the while imagining how cool their entrance is going to be.