There is a weakness within Spock's armor of discipline and procedure. That weakness is named Uhura, and though she cannot find a logical argument to do as the other woman suggests, Spock knows that it is inevitable she will comply.

"You are aware, of course, that should the ship determine us lost, they will likely initiate a rescue attempt." No matter what the Commander and the Communications officer happen to be doing at the time. To be caught in any, indelicate circumstance would mortify Spock right down to her stoic core.

Yet she leans against the other woman imperceptibly. Unwinding the smallest bit of tension.