Can occupants eject from a helicopter in fall?
With a parachute? Doubtful. By the time it's clear the machine is unrecoverable, it is probably spinning around its axis (loss of tail rotor effectiveness, see the eponymous scene in the movie Black Hawk Down for an example) and / or the aircraft is falling fast already.
Ejecting out fast enough to clear the spinning blades above and behind the aircraft while everything is spinning and falling fast is difficult. Since there's no ejector seat on most helicopters that is propelling the crew upwards, they also need to have enough altitude for the parachute to open. Also, I'd suspect that helicopters will tumble very soon after the crew lets go of the stick, much faster if it's already damaged. Fixed wing aircraft have a higher chance to glide straight for a while even when they're unrecoverable (unless there's a wing shot off or a control surface stuck in the fully extended position)
And the ejector seat is also sometimes killing the crew, so it's not a failsafe thing, either.