Well, not many. Lengths that is. As it turns out, he doesn't even protest all that much. There's no getting dragged down the prison hallways, kicking and screaming "I'm not the killer! I'm innocent!" Hell, even a killer trying to get off on the insanity plea would try and pull that one. Dennis just kind of mopes around.
Sure, he mentions it to his lawyer - that he's switched bodies and is in fact, Dennis Maloney, and not Richard "The Family Man Killer" Brautigan. And then...you know, he waits. For his lawyer to check on the story. Weeks go by and Dennis just sits in prison. Every so often he gets beaten by cops. He weeps a lot. Nothing overtly courageous until the very end. I'll give the scenario credit. It's a fairly nightmarish situation for anyone with a wife and kids. But it's even more nightmarish to watch the hero sit there and do nothing.
By the way, if you loved the graffiti in the haunted house from "Spooked" ("bodies in the basement" and "murder"), you'll love the prison cell that poor Dennis gets to live in. See, not only is he an innocent soul trapped in an imprisoned killer's body, but he gets to look at the tormented chalk-work of the condemned madmen before him. Men so undeniably evil that they're driven to write the word "Hate." Or "Hurt." Or my favorites; "Why me?" and "Punishment." I'm really still waiting for "Fart" to show up in some sort of wall-writing this season.
So what's the supernatural reason for the body-switch? Well, there is none. The whole thing starts with Dennis blabbing away on the phone while driving, and then getting into big collision with Richard, putting both of them in the hospital and near death. The two of them even meet up in the hospital as wandering spirits. Then the wackiness ensues as they wake up in each other's bodies. Take a little Face/Off and add a little Shawshank Redemption and then subtract anything good that those two movies had to offer and you can start to imagine this episode quite well. See, in Face/Off, they had Nic Cage escape from the prison right away. That's what we call "moving the story along."
In the end you'll probably just think Dennis was being unduly punished for using his cell phone while driving - which is why I can't wait for the "cell phone talking in cars" ban to take effect in California on July 1st. Sorry Tennessee.
The one interesting thing going here is that once the "Family Man" killer is in his new body, he actually wants to retire and redeem himself through Dennis' family. He sees it as a chance to find love and kindness. A bit of an implausible notion, perhaps, for a man that supposedly videotaped himself raping and killing whole families, but I've got to give a little bit here or I'll gouge my own eyes out watching these episodes. I did think that it was a new twist, and that being said, I should mention that this is the only episode so far that had a dour enough ending to kind of stick with me.
Oh and I forgot. There's a ton of Christian stuff going on here. And in the short tradition of Fear Itself episodes being as subtle as a wild boar on meth - the song "Amazing Grace" is sung over nine thousand times. But in the end, the religious beliefs that both Dennis and Richard both conveniently share add up to nothing. They just seem to be there to try and make a cruel and dull story seem loftier and more meaningful.
Since serial killers have been packaged-up and "cartoonified" to be America's vampire or werewolf, it's hard to recommend a good movie with a tethered, believable serial killer that you haven't already seen. You're a savvy bunch. So it's best to stick with actual history. It's much more terrifying. I recommend the HBO movie Citizen X about the profiling and eventual capture of Andrei Chikatilo.
And for an even more terrifying experience, watch the body-switch movie Like Father, Like Son with Dudley Moore and Kirk Cameron.