[the bitter edge in his own voice smooths out as soon as he hears the vitriol in the Doctor's, and he moves to perch on the edge of the bed.]

There's not much of a point to any of us in this place, is there? Anyone at all could be a murderer one day and a saint the next; completely useful when it doesn't matter and utterly useless when the only thing of importance is on the line. [a sloping shrug, and he swings one of his feet.] I can't say your dedication isn't admirable, though. If you're fortunate, it won't be futile.