“I do not believe in angels.”
But Humans do. They believe that every second longer their life continues brings a new chance, a most illogical notion in this particular case, when with each passing second the odds of their survival decrease. Calculating: the search grid, the time it will take to reach the Enterprise's destination at maximum warp. If Spock had the conn right now, with Jim somewhere below, he would be determining the maximum time he could spend searching and still deliver the medical supplies in time.
The time is up.
Factor into this equation the human James T. Kirk. When no obstacles present themselves, Captain Kirk abandons his crewman 0.00% of the time. When there is physical danger, he still comes 83.4% of the time. When coming would be in direct opposition to a command, he comes 46.2% of the time. The chance is that the Enterprise is still in range, and –
He jettisons the fuel in a instantaneous weighing of cost and benefit. The orbit will decay if he does nothing, and they will perish. But assume the Enterprise is in range, assume they are still scanning, and assume Captain Kirk will act as his nature dictates. The assumptions are reasonable; the outcome uncertain.
To panic is illogical. Mr. Scott, at least, smiles like he understands.
Spock summons his Vulcan control and blocks out McCoy's indignation. His actions on the planet, however logical, led to the deaths of two people. But his actions in this moment are logical, correct, and he does not, he will not, regret them.
They have survived. Jim and the doctor circle around him, not unlike the birds of prey that circled the skies of Vulcan.
If he explains the logic behind his reasoning, he can extrapolate from past instances that McCoy will mutter “cold-hearted computer” and Jim will blink at him for an uncertain moment before turning away.
This is unacceptable.
Instead he tangles his words and hints at admittance, allows them to trap him in illogical arguments.
Just as predicted, Jim smiles.