we have found out, that you can glitch through a closed door with your weapon drawn.
This is almost possible for every door.
You can do this with basically EVERY "not so thick" Object + known "Bug/Glitch/Feature/WhateverYouCallIt" since... erm... I think OFP Release was 2001 ;)
Oh wow, i play since Arma 3 release - so if this bug exists since 2001 it's definitely worth fixing...