Whoa. Fingers crossed this is a sign that the movie will be good and not that things are so awful on set that Gyllenhaal feels the need to put his fist through things on a regular basis.
Jake is currently filming thriller Nightcrawler in which he plays 'a freelance crime reporter who stumbles upon the dangerous underworld of LA', and has lost a whopping stone and a half for the role making now resemble something absolutely terrifying. Anyway, Gyllenhaal was filming, and had been doing so for 18 hours, and during what was described as an 'angry scene' on Wednesday when he had the outburst and apparently punched a mirror while in character.
According to People: 'The scene was emotionally charged and his character was talking into a mirror and he got so into it, he banged his hands against the mirror and it broke and cut him. It was all the scene and not because he was mad about anything else.'
Gyllenhaal was rushed to hospital when his injury proved to be a lot more serious than thought, and he required several stitches in his hand. It's not yet known if the scene will make it into the film, but it does sound like one of those 'too good to not include' scenes that not only adds to the film but also makes for a great story come junket time.
Honestly though, he was probably just hungry. We're mean when we miss lunch by an hour, and have you seen Jake Gyllenhaal lately?