Nowadays, you'd have to reeeeally be distracted to let one stall
I don't follow. Have they made seconds longer since 1985? You still have <2 seconds to realise what has happened, get your hand back on the collective if you happen to be tuning radios etc, and get it down. Maybe you're more aware of it now, but thats all.
In this case there was an experienced instructor with loads of R22 time on board. Didn't help.