I agree with you Charlie, no paw prints mentioned.
I think Meredith would've said to Brent if the dog was locked in the bathroom, laundry, den or where ever (ie; the dog was freaking out in the **** when I got here), so I tend to think the dog was outside freaking out at the back door.
The first thought I had that (for me) put the dog outside is that I don't know any dog that wouldn't be tempted by the overpowering smell of a 'kill' (sorry about the awful reference
but I can't think of another word) and be able to control itself and not lap up blood.