There is a hint in the tag: The nightmare is real. It may be the intruders originate with the protagonist somehow. The blanked out mouth suggests that as he would not be able to articulate what's going on even if that were the case.
I'm sure we'll get a new cut within a few days, but you might want to take a look at the trailer. There is another hint that supports the above. In the trailer, only Owen's character has seen the intruder. In fact, the police (and possibly his wife) think he might have a screw loose.
Clive Owen brings a credible every man feel. I've always liked him. Director Juan Carlos Fresnadillo did a very nice job with '28 Weeks Later' and 'Intacto'.
I've heard mixed comments but look forward to this one. My kind of flick.