I agree they shouldn’t stop him, but you describe him as wandering through the tunnel onto the Island of Doom as if he didn’t meet anybody on the way there. It just seems strange that he wouldn’t. Besides even if both locations are secure, one is still HQ and one an outpost. I would think there would be guards, just so that nobody could sneak through at least… I mean assassins, shadows, and what not. Also on the Abyss side you have a lot of maybe not all too loyal demons (Lillith’s guys) with a straight path out of the Abyss. I know Tom has a link to them, but out of almost two thousand demons one or two are going to test it given the opportunity.