OOG: He's still there, he just can't see anything. everything he could SEE dissapeared (from his sight), but he can still smell, hear, and feel his suroundings (The damp floor under his paws, the scent of the cat's trail on the floor ahead of him, etc).
In other words, something has blinded him. Sorry for the confusion, I should've been clearer.
IG: As Corlon creeps closer, he sees Garret standing in the hallway, his eyes glazed over, though he's still resonsive. (You stopping to see to Garret or continuing on to see the dragon?)