S3. EP.41: - When Ned wedged his third ransom note between the bars of the grille, Ebony happened to be in the shadows watching him. But instead of blowing the whistle on him to Bray, she writes a new version of the note and leaves it, once again, in the grille. When Bray reads it to everyone in the morning, Ned explodes, for that isn't what he wrote, but he must be careful not to give himself away. He leaves the Mall immediately. This is what Ebony hoped for. She secretly follows, and discovers where Ned is keeping Amber and Trudy.
Ned certainly has a real key, which he really turns in a real lock. You can see the latch-bolt disappearing into the door. And that's the goof. If you can see the latch-bolt straight off, the door wasn't actually closed properly. But hey! You can also see that too. Ned doesn't actually need the key at all. Anybody could open it.