Why does this passage use the imperfect subjunctive?

Question

I'm reading Harry Potter y la piedra filosofal and the following passage has me a tiny bit confused gramatically (I understand the meaning though):

Quirrell se apartó, con el rostro también quemado, y entonces Harry se dio cuenta: Quirrell no podía tocar su piel sin sufrir un dolor terrible. Su única oportunidad era sujetar a Quirrell, que sintiera tanto dolor como para impedir que hiciera el maleficio...

Initially I thought the que here was a subordinating conjuction (can you use que all by itself like that in Spanish, or would you need something like para que instead?), but now I wonder if it's actually introducing a nominal clause, as if the text were Su única oportunidad era que Quirrell sintiera tanto dolor....

Am I on the right track? Gracias!

Answer 1

The function of this clause is adjectival.

que sintiera tanto dolor como para impedir que hiciera el maleficio

is describing Quirell and how he would feel.

Su única oportunidad era que Quirrell sintiera tanto dolor

The way you rewrite the clause is nominal- that is Quirrel is actively doing the feeling of those things.

Just to clarify que and para que are both mechanisms for introducing subordinate clauses- whether they be nominal, adjectival, or adverbial (I would think Para que would be most commonly used with nominal clauses, though).

So yes, que can be used in this way.