I have a Nikkormat FT3, and I forgot to press the rewind release button before turning the rewind knob (yes, stupid, I know). There were some weird sounds coming – the forcing of the film I suppose – but after a very little while the knob felt loose. I think the time it took was too short for the whole roll to be rewinded. Any idea what happened? Should I open the camera? I really don’t want the film to be ruined.