I think there were lots of different underground levels in the research base.
When the soldiers went in, they found an unhelpful scientist (not a priest) on the first level.
They left him there with a soldier whilst other soldiers went to the lower levels.
They were then pursued by some kind of creature.
Can’t find this film anywhere. I only know that the film was NOT called The Devil’s Tomb. It was a film similar to that, though.
Thanks everyone.
Question is closed for new answers.
pori Selected answer as best Jul 15, 2022
Maybe:
The Superdeep (2020).
https://www.imdb.com/title/tt11815960/
https://www.youtube.com/watch?v=aO6gYI_LXBo
Mike_Marshall Posted new comment Jul 12, 2022
Very good effort, and thanks for replying. But it’s not The Superdeep. I’m pretty sure the movie I am looking for is older than that. Thanks again.