The Death and the Maiden quartet

Hi, I just watched yesterday "What?" and I noticed a curious thing, i.e. that the score often (e.g. to accompany Sidne Rome's wandering in the villa or during her pursuit from all the inhabitants at the end) makes use of Schubert's quartet "Der Tod und das Maedchen" (or "Death and the Maiden"). What I found remakable about that is that more than 20 years later Polanski shot a movie based on a play with that title and where the same quartet plays an important dramatic role! That's quite remakable also because between the two movies there is no other apparent point of contact: is it pure chance that the same quartet is heard in both movies? If someone has some idea, let me know, thanks.