A last

"Perhaps he was just a figment of her imagination-A LAST, desperate escape from the lonliness of her life".
Czy w tym przypadku "a last" znaczy tyle co "another"? Wydaje mi się że to dość rzadko spotykana forma.

a last, desperate escape w czym problem?

nie - 'a' odnosi sie do 'escape', ktore jest poprzedzone przymiotnikami 'last, desperate'

Przyznaję że nie do końca rozumiem użycie "a" w tym zdaniu. Raczej spotyka się "the".
Np. "Won't you give me a last chance?"-o ile mi wiadomo w tym zdaniu "a last chance" znaczy "another chance".

Spotyka się
a last chance, attempt, appeal etc. Why not escape?
Cambridge dictionary:
British police are supposed to use guns only as a last resort.

"A last chance, resort, request, attempt, appeal,…" are seen and introduced by the speaker into the discourse and recognized by the hearer as (often nonspecific) instances of those dramatic situations that we call "last chance, resort, request… "

"A last chance, resort, request…" do not mean "another chance, resort, request..." A prisoner sentenced to death is traditionally granted a last request and not another request.

You could say, "Give me the last chance" when you really plead for forgiveness for the last time (after other chances that were given to you before), but this can also give a hint of "the proverbial last chance."
Or, alternatively, it could also mark the latest of "last chances" in the sequence of chances given to you. This latest would be viewed now as a particular chance-giving event in the time domain.