Why are there no Underground areas?

[Why are there no Underground areas?]

well, some maps do have things that can be said to be underground, like tunnel in the invation44 mod ?

But ai pathfinding is a bit screwed in those areas

[Broken bones, no morphine, not fun.]

another nice solution, would be if you could take the painkillers, and it would help, though, you wouldn't be able to run, and got the shakes, and afther 30-40 mins, you'd need a nother round of meds to keep on going ;) til you got an injection, or 3-4 hours gameplay, with painkillers used as mentioned