If a talmid chochom and a plain yid are drowning at the same time and you can only save one, you should save the T”C.
That’s NOT the same case at all. There, both parties are at jeopardy, and, therefore, if you can only save one, save the TC*. Furthermore, in that scenario, you are not actively doing anything to shorten the life of the fellow who is drowning… you are merely not helping him because you are already busy saving someone else.
Here, the other party is not at jeopardy AND you are *actively* doing something to save someone else. A better scenario would be this:
You see a TC is about to be hit by a car. You can’t save him directly, but you *can* save him by pushing someone else into him, causing the TC to be shoved out of the way, even though the other person will be killed.
There is NO WAY that such a scenario is permitted — no matter who the other person is — whether he’s a talmid chochom himself or the biggest rasha.
The Wolf
* and then, I’d say that you save the TC only if saving him is more certain or of equal chance. If, however, you have only a 10% of saving the TC and a 90% of saving the regular yid, you go for the regular yid.