Owen didn't know about secret doors, but it was possible the house had them. Because yes, They had to be getting in somehow, and it seemed far too easy to just use the front door. But if they were all drugged at night as not to wake up when They were doing whatever it was they did, then They probably could just use the front door.
"I don't think anyone is looking to be running or jumping at the barriers recklessly," Owen told Pam. "That's not what we're talking about. We'd test them with caution, to try and find out how far we can do, and what the perimeters are around the town. I'm not too keen on anyone trying to push past the boundaries, because we have know idea what would happen, or what They could do to one of us if we actually made it through and ran for it."
He thought about the implants a lot, and what they could be triggered to do. One push of a button could be the end of any one of them. "There's just too much uncertainty to take that kind of risk right now. As for messing with their signals, that's beyond me," Owen added with a faint grin. "But if you look at this place, what they're capable of doing? I would think they've got all those problems figured out."