[Starwatcher2001]

I seem to recall that "Drain" spun up the motor on the floppy drive to create the spin dry cycle.

[AnimalMuppet]

If I recall correctly, the drive light stayed on, the drive was spinning, but the whine came from the speakers, and moved to a higher pitch partway through. It also smoothly ramped down in "RPM" (frequency) at the end, which is not a thing that the floppies could do.