I am using Z table for Blue rooms and I found Never-ending Tunnel with test Breaking the magic.
Because my INT is quite low (Warrior) it is hard to pass test, which is ok it happens. However my question is if Successes should be below 0. If yes, I think my hero will stay there forever :)
The automatic success rule (p13) give you a very slim chance of escaping the tunnel. Fate points could be used to manipulate the dice/die result. You could also unofficially decide if the adventurer dies and you use a Life Point it also puts you out of the tunnel.