Actually, I think he’s talking about 4e. The DMG2 (IIRC) discusses using multiple rooms when building encounters. Instead of budgeting room by room, you build over an area with an objective in mind. It’s sort of a middle ground between combat as sport and combat as war. You’re still designing with appropriate encounters in mind, but the scope of the action is bigger than just one fight in a room.I hope you're still talking about 5E or Pathfinder 1, because when it becomes "all a big battle" in Pathfinder 2, then is when the heroes start dying...
For example, suppose the PCs need to make their way past the barracks into an enemy base. You would budget your encounter for the entire barracks complex as e.g., a severe encounter and not just room-by-room. If they’re clever, the PCs can engage it a piece at a time or even bypass it. If they screw up and someone raises the alarm, you’re still okay because you budgeted for a complex-wide fight.
For a PF2 official adventure, you’d want to look at an area to see how the combined encounters added up. If they’re together an extreme or worse encounter, then you can’t really run that area dynamically. If they’re not, then I don’t see why not because you know how dangerous the encounter will be in aggregate. And if it’s too dangerous, and you want to run it that way anyway, then just change it. The CRB says that’s okay.