I read davidt1's post earlier, and my interpretation was that he "killed" the cell, not just discharged it. Maybe that's not what he meant though.
I know from running high power AA and AAA cell lights, that it's pretty easy to run a NiMH down lower than it should be. All of my AA and AAA lights that also run 14500 and 10440 cells, have a voltage check or auto warning/shutdown, so I've never had any serious problems.