Off and on, with a break here or there for another scene or so, it's been going for 12 pages. Same location, same situation. A bit of dialogue to break up the action/narration. But it's the same place, and the same scenario. I want to know should I shorten the scene up completely, or would it be alright to continue with the scene, but putting in a break here or there for flashback scenes and such? How does this work?
It'll work providing there's enough going on to keep the reader interested. Make sure it doesn't get repetitive. If you bore your readers, they'll stop reading.
It all depends on whether there is enough taking place in the scene to warrant twelve pages. As long as the scene keeps its momentum, there's no rule I'm aware if that would require you to interrupt it. However, even if it remains in the same location, that doesn't guarantee that it is the same scene. If the cast of the scene changes, or is a new activity begins, it's really another scene. You could have an entire story revolving around two people in a sunken research minisub. They remain in the same cabin for the duration, but new complications generate new scenes.
I'd have to read through it, but it really depends on the scene itself. Why not try this? Go back and read the scene, as just a reader and not the author. Read it out loud if you have to. Who knows, you might just answer your own question.
It's already been said, but it is worth repeating: if it is interesting, it will work. There are no rules to writing, aside from Don't bore the reader. If you need proof go watch "The Man From Earth" -- the entire film takes place in a cabin, and relies entirely on dialogue to propel the story (and it works, in my opinion).
Personally, twelve pages sounds pretty daunting, especially with no dialogue. As long as something happens, you should be alright. Do you go into huge depth with describing the location? That's the one thing which usually puts me off - huge paragraphs describing the landscape or the exact shade of the MC's eyes.
No I am actually terrible at description! And I have dialogue; as I said, the scene is broken up here and there by dialogue. But it's just there isn't a whole lot of *action* going on, and this is because the scene still has to resolve the issue of getting my MC to safety.