The view in the mirror is relatively normal. It looks like we’ve come back in Damien’s body. Great! It worked!
However
Here the mirror’s cracked and we see the world in the reflection distorted. We’re now seeing Dark! He threw us out and put us in the world where he was. We let him in, he pushed us out.
It’s evident we’ve been tricked by him because:
Dark WALKS AWAY. If we were Dark, we would have turned with him, we would have seen the house as we stepped through but we don’t! We’re stuck! Dark left and got exactly what he wanted!