There were a couple of things that didn't quite add up in the description. One was the notion that a section, once cleared of monsters, would stay cleared. That wasn't plausible at all--wait a while and it would fill up again, albeit with less dangerous critters (if they were more dangerous, they'd have pushed out the original occupants before you got there). That would include your victorious return journey--you'd have to fight your way back out too.
But it was the cleric that bothered me. True, these were based on pagan gods, which have consistency problems of their own. But as a rule a priest doesn't get to tell the gods what to do (although the Egyptian spell books might suggest otherwise); his god tells him what to do. And he might.
So, if a cleric can get a divine command at any time to leave and do something else, what would induce the party to invite him aboard? The team could get divine graces for a while, but they couldn't rely on him to stick around for the whole adventure.
My solution was the "geas-ite." If your cleric got a command to head somewhere, he had to light out right then, but he got divine protection along the shortest way out--and so would his companions so long as they didn't try side-trips. "In a jam and want to bail? Have the cleric check his mail." Would that be "d-mail" for "divine-mail" or "g-mail" for god-mail?"
I never got far enough to figure out which game-play mechanism would work with that concept--D&D play was far too time-consuming and I only lasted the one session. As a scheme for letting (most of) a team get a second try at a dungeon it seemed plausible, and it seemed more faithful to the nature of a cleric, but whether it would actually be playable I couldn't begin to guess. I haven't checked the rules in more than 40 years.
(The DM would, of course, repopulate the parts of the dungeon you'd already visited, thanks to the ecological principle I mentioned at the start.)