Someone's Knocking at the Door (2009)

Two twisted serial killers return to the medical school that once made them victims in a cruel experiment. Now, they unleash their sadistic vengeance on a new group of unsuspecting med students. As the body count rises, the killers employ horrific sexual violence as their method of execution, turning the campus into a nightmare. With a blend of horror and dark humor, the film explores the gruesome consequences of their twisted past, leaving viewers on edge as the chilling events unfold.