Very cool to see Sean Maher pop up on the show. Without knowing anything about the character, my immediate reaction was "don't kill him off". Why? Well that should be obvious. I want to see him and Summer Glau share a scene together. Any fan of Firefly will want the same thing. Good thing is that he survived by episodes end and is now incarcerated. So, we may get that mini Firefly reunion down the road. Turns out that Sean is playing Mark Scheffer / Shrapnel, who has a history in the DC Comics Universe. Personally, I've never heard of the character till now.