I am hoping to play Thomas as a man whose central strength is ability to think analytically in stressful situations. I want to play Thomas as a foil to the emotionally-driven other characters, and one who will follow his essentially utilitarian ethics up until the absolute last. I doubt Thomas will willingly sacrifice himself based solely on utilitarian evaluation, but besides that I am going to play the character like he has time to make these quick judgments.

He will, obviously, attempt to do all he can outside of combat in a hypothetical ambush, trying to do the most overall good [if the Emperor is there, for example, he would judge the political strife of the death of an above-average ruler would be worse than the kid's sadness at his dead father not being there to see his soccer game].