Locks(2004)

Overview:

Martín, an attractive young man in love with his girlfriend Paula, wakes up worried. Without knowing why, he feels severe pain in his anus. He goes to the bathtub to try to relax, but begins to bleed. The bathroom door is unlocked and his roommates are about to arrive. What to do when you don't know who you are, and life is full of locks (and closets).