What's a reasonable shutter speed for low light + fast lens?

Hello!

I recently purchased a Canon FDn 50mm F1.4 lens for pairing with my Nex-5R. I enjoy taking pictures in low light situations which is why I made the jump (as well as the relatively low price point for legacy lenses).

My question is what is a reasonable shutter speed expectation for typical low-light indoors with this lens speed? I was really disappointed last night shooting at around 1600-3200 ISO and between 1/20-1/50 shutter speed. I guess I was expecting a miracle from this lens being able to shoot at 1/250 in similar conditions.

Are my results typical for this lens speed or is it possible I'm doing something wrong? the subject is generally people moving about, not fast but also not portrait-still.

thanks!