The first girl who seems like a leader of this group was offended by the fact that Grace was not responding to them.
So enraged, She raised her hand and then without any hesitation slapped Grace.
As that slap landed on her cheeks, Grace for a second or two did not understand what just happened.
This is a well-reputed school. She never thought that these women would go past their normal taunting as it is a serious consequence of the act of violence.
"Bretta, Violence is not allowed on campus, What do we do if she complains about us?"
The other two women with Britta reacted and were horrified by her action.
It's not like they never beat anyone, It's just that rules against violence on the campus are very strict.
If teachers find out that they did something like this then they will definitely go get expelled without any question at all.