Jon, you're misunderstanding the periscope we're talking about. Your head is still tilted forward but you are looking slightly up from horizontal to the ground level & it's really very natural. It's common for long tanks to do a windshield/window in the nose, this is just a different variation of that same driving position. It seems you are under the impression the driver is looking straight up (vertical) & thats not the case.
Sid.