Chariot's onstation, no worries. Let's break some barriers.
1. If you can't get back the way you came and the place you're in says you can't go forward, that's a fail state. You're trapped Belter. Ain't no way forward or backward. Now I've heard some folk like to play it where you go back before the one-way door and keep on keepin' on with those cards showing blocked. I call that "Belter Psychic" mode. Your choice how you want to roll with it.
2. If you fail the roll, you're trying to make entry into a module that you can't Transit from. Bulkheads won't open, so you gotta go for another swim. You can always spacewalk from any module adjacent to empty space to any module adjacent to empty space, but it's never a safe option. Say a little prayer and keep your nerves steely.