Help needed

OK, I am at the exit portal from the telepert maze. I did the thing with the gambling Cambion, and won the knowledge of the way out. I did go back a few rooms to whack the Wraith Lord, and also some Demon Knights in yet another room. However, when we go back to the exit portal, apparently we need something else in order to leave. What am I missing?
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.....So, she then took us to the Gambling Cambion. He of course is scripted to win every wager, but he did toss us a sceptre gem before booking off to another dimension. Now, since the wager I made with him was the way out of here, I assumed that I could just use the teleport device in the room. Alas, he was less than honest with me. Oh no! A demon who was dishonest?? I am shocked to the core! Anyway, I seem to be lacking something to be able to leave. I suspect i am going to have to retrace my steps through the entire level in order to get the remaining two gems. And all this after whacking the Wraith King and slaughtering a roomful of Demon Knights. What a bother!
And the Cambion is not scripted to win! You can beat him and get the Spectral Brand and Wish scroll. But I do find the odds are against you, and multiple reloads will likely be required to win.
Regarding the cambion's game, you have a 25% chance to win in the first hand, a 50% chance to win in the second, and a 0% chance to win in the third. Regardless of what you're playing for. The cambion is entirely honest about the game, and even lets you have the gem and scepter when they leave (if they win the "way out" from you). None of that party is evil. Though if you're feeling evil or paranoid, you can pick a fight instead of giving up the scepter, and take the Deck from the cambion's corpse.
(I'm using they/them pronouns because that cambion has the "NIETHER" gender)
There is a possible route through the maze in which that teleport represents progress, but if you've already dealt with both fiend leaders the succubus is mostly just teleporting you past rooms you've already cleared.