You can't go back the way you came because the secret door you went through closed when you found the staff. You'll have to find another way.
I'm sorry that this quest has turned out to be much harder that it should have been, I said at the start that I wasn't sure if it was going to be too easy, too hard or too balanced because I've never designed a quest for eight heroes before, this was always a bit of an experiment and it turned out that I overestimated the power of eight starting heroes. I was expecting more spells to be blasting the monsters from the two wizards and the Tzeentch Staff. I thought the mass healing and Bravo's resurrection would have much more of an effect but the freakishly good dice rolling of the stone chaos warrior basically cancelled it out. At least now I'll have a much better idea of how balance later quests for more than four heroes, the next ones will have four as I explained in the PMs.
You could still get another Mentor restoration and you're not doomed just yet even if you don't. I know it's not ideal to hope for a rule that's not working the way it was intended to help you but just think of this quest like the trial, that's what it was originally going to be based on. The first quest is the best one for the heroes to die in because you've got nothing to loose. If they all die then we'll just go into the next quests with a new set of heroes. I hope the difficulty of the monsters hasn't spoiled your enjoyment too much. Like I said, just think of it as The Trial.
Sotiris wrote:Salvo opens the dooor...
Nothing to add to the map.