Matt's family
There's a possibility that Matt was lying about having a wife and a daughter - one, it's too much of a coincidence for both central characters to have been blocked by their spouses and their offspring, and two, it seems a bit odd that a seasoned manipulator like Matt couldn't make up a lie about why he was carrying a hard drive around at night, even if he was on the spot at the time. Maybe Matt made the wife and daughter up to try and forge a connection between himself and Joe, in order to make it easier for the latter to confess.Joe's cookie has a way out of the million-year torture
Namely, just break the radio repeatedly, as fast as possible. The volume will very quickly grow in geometric progression to such a level that's impossible by the laws of physics, either causing a numeric overflow in the underlying software, or frying his own consciousness.