Like most other powers in 4e, if you look at it in terms of the game narrative, it makes perfect sense.
"Unconsciousness" is a mechanical term that could entail any number of narrative descriptions.
"With a mighty swing of his tree-like club, the ogre knocked Nyreth the Nimble to the ground. He lay there bleeding, barely clinging to consciousness. All of a sudden, the voice of his comrade Rindale rang in his head, 'Nyreth! Throw off your wounds! We need your help!' With a renewed resolve, Nyreth managed to find the inner strength to hold onto consciousness just a few minutes longer."
So, yeah. The status "Unconscious" just entails a list of game effects. It doesn't necessarily mean the character is ... well, unconscious in real-world terms.
-O
It's the basis of how my alarm clock functions, for example.There's also a long list of evidence of people who are actually unconscious still being able to hear.
YouStop being a little baby and get up. Life is pain. Get used to it!

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.