A portion of my dog's ear was torn off..?

First off - I already took her to the vet. She is in surgery now..I just have a few questions about it.

And we have NO idea how it happened, no one was in the room!

Anyway, what I was wanting to ask was:

Has this happened to anyone else before? I'm kind of scared about it.

Does it ever heal 'normal'? I really don't know how to explain this..It kind of looked like a piece of paper, 'jagged' is the only way to describe it. It was about (more or less) 1/4 of the ear. Nothing TOO major that the surgery won't fix.

What is strong enough to tear the tissue of a dog's ear? We have a few flower pots in the room, but nothing sharp. My other dog was there, but he was a rescue and doesn't have many teeth. The one's he does have is SMALL. He has a hard time chewing bread, let alone skin. If we give him a raw bone he has a hard time getting through the thin skin if it has any. So it beats me how it happened.

Sorry I'm asking so late. I just got the chance..we just got back from the emergency vet and I won't get time to ask tomorrow. I'm going to have to take care of her.

(This is the dog that's in my avatar, BTW).

Thanks you! :)