Okay, so in the Dalek Mod 1.8, the 80s TARDIS does not have a door animation.

Now you might be saying "well wut doz dat do"

It lets anyone and everyone go into your nice 80s TARDIS exterior, as it doesn't have an animation like the other TARDISes

(might be something else, but that's what I infer)

This exploit can be used to grief and illegeally enter a TARDIS, and is a known bug on DMU.