I usually set three alarms at 15 minute intervals. I have sabotaged myself by rolling over half asleep and turning off my alarm. Not sure that would have helped the OP though, depending n the type of alarm and the duration of the humming episode.
I feel you. I wake up at least 2-3 times throughout the night, yet I most mornings I cannot heard my standard alarm clock or iPhone alarm! Although I can hear if either one of my kids makes a sniffle in the next room! =\