Questions & Answers about Gdyby nie ten chirurg, mogła umrzeć.
Why is ten chirurg in the Nominative case instead of the Genitive? (After all, there is a nie right in front of it!)
Normally, negation in Polish triggers the Genitive case. However, the fixed phrase gdyby nie (meaning "if it weren't for" or "had it not been for") is a special exception that takes the Nominative. That is why we use ten chirurg instead of the Genitive tego chirurga.
Why does the sentence use the regular past tense mogła instead of the conditional mogłaby?
In Polish conditional sentences, if the condition is already clearly established with gdyby, native speakers sometimes drop the conditional -by particle in the result clause. Using mogła here instead of mogłaby means exactly the same thing but makes the near-miss feel a bit more immediate and dramatic.
Does gdyby nie only refer to the past?
No, the phrase gdyby nie plus a noun works for both the present ("if it weren't for") and the past ("had it not been for"). We only know this sentence is about the past because the second verb mogła is in the past tense.
Why use umrzeć here instead of another word for dying, like zginąć?