It's interesting, she can probably pretty clearly see the patches of colder substance arcing through Soldat's body, the metal supports for the metal arm, and the arm itself is clearly colder than the rest of them. The little ghost is heat-free, and sadly, the train walls block any head signatures that the void outside might give off.

She might be able to see through the carriage doors into the next, though, if there's any people in the triage car to see.