Boarding School Students Find Bloody Eyeball on Staircase

by Brandon
(Syracuse, New York, USA)

I'm wondering if anyone can help me remember the name of a film I saw years ago about two friends or sisters at a boarding school.

In the end, people are looking for them and they along with the headmistress are climbing up a staircase. There's an eyeball and blood on the stairs as they continue climbing up to a higher floor and open a door. The three of them are covered in blood.

It's not May. Does anyone know what film this is? I really want to see it again, so any help is appreciated.