Except old frail people are armed with canes and oxygen tanks, which probably hurt worse. And most of them are strong enough to handle being startled and not worry about heart attacks. Granted this FML would have been more complete if the Op lost his job over this. HE would have definitely lost his job if an old person had a heart attack.

I know some frail, old people are armed with prosthetics and life-support systems -- the OP should have stayed hidden while these ones walked by. But, as far as losing his job is concerned, if he worked at a funeral home, he'd be awarded Employee of the Month for drumming up business! :)