In the movie, No One Lives, there's a scene where the "Driver" plays a "sociopathic game" with his victim, Emma.
He slits his own throat and later appears to have healed.
How exactly did this happen? How did she "save" him (as he claims)?
He cut his own jugular, but beforehand he explained to the woman (Emma) how to staunch the wound and dress it so that he would not bleed out and die. This is revealed in a cut scene as a flashback.