Now that I think of it, it could very well be "Mark of Gideon" --
Clues:
Camera angle is dutched, denoting an unusual viewpoint or situation -- as in an empty ship..
Spock is carrying a tricorder -- unusual for him on board, unless he is "looking" for something... in this case, maybe scanning the replica enterprise.
For the same reasons, I also thought it might be "Obsession" (scanning for the vampire cloud) or "Day of the Dove" (scanning for the alien force).
But, I've talked myself into "Mark of Gideon."