The Moon locked me in secret room during Challange #3
Solution 1:
I'm calling glitch. The game is supposed to allow you to leave via one exit, but for some reason the exit it has chosen is linked directly to one of the "special rooms" which you haven't activated yet.
Since it's a special room the game will not allow you to access that auto exit without a bomb.
It's either that or there's an enemy inside of the room, but I don't see one.
locked in areas is rare in my experience but possible. I once got teleported randomly (curse pearl), into the middle of one of those rooms with the center blocked off by unbreakable blocks and no way of getting out without resetting.
Basically this run is now not able to be completed sadly.