The decision is not made until during surgery.

Why does this bother me? Is "during" a precise enough time to mark "until"?

Granted, some limiting events may be prolonged, but isn't "during" deliberately prolonged?

I just can't seem to swallow it.

". . . if I have to sit here until Hell freezes over!" (no problem)
We don't really care if this means until it starts to freeze over or untill it's completely frozen over.

I'd have no problem with:
until the time of surgery
until sometime during surgery
until surgery

Many thanks, - A.
It doesn't really 'bother' me, in the sense that it sounds like a pretty normal informal utterance. I don't see that precision or duration enters into it, really-- it's just the juxtaposition of prepositions that we are unused to: until (sometime) during surgery.
Thanks, MrM.
I read somewhere that one thing we don't lose as we age is our ability to reason.

But I find I'm relying more on instinct and less on logic. Hopefully, common sense resides somewhere between the two.