Her comment went unnoticed, primarily because the opinions of others on superficial matters were unimportant. "I meant in the sense that you exist parallel to someone else. You are different from the other humans I have experienced thus far."
Castiel had meant no offense, but if she was going to take it, that was her problem. He wasn't going to apologize either.
"We need to rule out possible culprits first," he continued, jumping right back into the problem at hand. "If the angels were here, I would hear them. Sense their presence, so it is safe to assume they are not here and the longer I am away from Heaven, the more it is likely my Grace will wane. What do you know of that could cause this?"