I would have assumed that if a sawzall was already drawing blood from your freaking neck, it would be too late to save yourself. Unless it wasn't on when she started cutting him, which would make more sense because those things are too loud to not wake the victim. An unpowered sawzall would be a very ineffective weapon or cutting tool.
Which just brings up the question, of all the tools you can use to easily kill a sleeping person (which, I suppose, includes every dense, hard, or edged object in the house) why use a powered saw?
But seriously, if the guy was still in the same house with the ***** who attacked him with a hatchet, then his head isn't doing him much good even while attached to his shoulders.
I dunno. There's almost too much stupidity going on in this story to be believable on either side. If it weren't for the infinite potential stupidity of human beings, I'd say this whole story was bullshit.