The difference between the outer & inner doors is more likely a function of the desktop theme, since it has changed.
In the Hartnell era, there was no "foyer", you could see straight outside. Not sure about the Troughton era.
I wanna say Tom Baker's Victorian auxiliary control room exited into the foyer.
Capaldi's Tardis sort of points to that--with shelves--but is also high tech--with good console work
I rather liked the foyer myself.
In terms of design, there are some tricks done via optical illusion (Brain Games and others) that a set designer might use--like some of the spook houses in the US:
https://skepticalteacher.wordpress....ation-of-the-montana-vortex-house-of-mystery/
Might be nice touch to a Tardis set.