Monitor Freak-Out

I woke up in a panic at 2 AM because I realized the baby monitor wasn't plugged in and the battery had gone dead.  With Korra sleeping in her own room and our doors closed (to keep heat in and cats out), I can't hear her at all without the monitor.  Plugged it back in and sure enough she was crying.  No idea if she'd been awake 2 minutes or 2 hours, but either way I felt terrible.