[FairyKing]

Actually, that does look like it's supposed to come off, to me anyway.

I say that because we can see the chestplate is connected to something with screws, so the designers could have just screwed it directly to the hatch that flips up, but they didn't, instead they screwed it to that gray bit that only holds onto the hatch by one little peg. There's also that channel in the top of the hatch, which doesn't seem to serve any purpose beside letting you get your finger in there to pop off the chestplate.