I don't recall that model exactly, but most of the Mitsubishi's that were too large to fit through a door had a way of hinging the mirror into the back of the set. It usually required removing about four screws around the mirror protrusion, lifting slightly and it swings in.
If it is one that the mirror hinges in it uses philips screws. Some have allen or philips screws on the side that allow the top section with the mirror to come off. I do not recal the design of that unit specifically.