It seemed that Daphne had stopped Jacob and Mary just in time, because if they would have pried the gate open just a bit more, they could have at the very least looked through the crack and would have seen what was outside of the privacy fence.
And what was there?
Nothing.
Yes, that's right. Outside the pool area and the privacy fence that surrounded it, there was nothing but a foggy limbo. Even if someone were able to leave, there was nowhere to go.