The director reveals Cam Gigandet, Nicolas Cage and Nicole Kidman were left battered and bruised following the film's most dramatic and violent scenes - and he was glad there was someone nearby who could stitch them up.
Schumacher tells WENN, "I was gonna put a card at the end of the movie saying, 'No animals were hurt making this movie but every actor in it was!'
"Nic (Cage) got a very mild concussion when Ben (Mendelsohn) slammed him on the floor in one scene at the beginning and Ben cut his eye open in another scene. Nicole was just black, blue and purple (bruised). Cam smashed this subzero refrigerator so hard in frustration he ripped the top of his hand off.
"We always had a medic, who was an ex-military medic, on set just in case anyone got hurt. There were accidents and no one planned them but when you have actors with this intensity they don't stop; they get lost in it."
And it was Kidman, who plays the victim of Gigandet and Mendelsohn's violent intruders in the film, who was the one calling for her male co-stars to treat her rough.
Schumacher adds, "Nicole felt sometimes they weren't being rough enough with her and her character could've gotten away, so she would say to them, 'No, that's not hard enough.'
"There's a scene where Jordana Spiro, who plays Ben's stripper girlfriend, is holding a gun on her and she is grabbing her by the hair and I remember after the first take Nicole said to Jordana, 'You know, you have to grab my hair much harder because I can pull away from you.' Nicole was great. I was not crazy about her doing her own stunts but she was down for it."