I've only been playing DayZ for a few days. And I was wondering if there is some kind of pattern or tip about doors and ladders etc, to see if they are intractable from a distance. For example, I have a theory that only Blue doors can be opened, so from a short distance I know that I can get in there. Providing there are no Zeds in there starving for some good brains. Does anyone know if my theory is right, or is it just a coincidence that red and brown doors can't be opened? Also is there any tip like this about ladders? Thanks, Dep.