John doesn't jump when the door opens, but his eyes do widen a bit.  "I really don't like the looks of that..."  He says softly as he peers into the darkness that was the door, and now the door way.  He slowly makes his way over to Mars.  While not at his best, he can still handle himself fairly well, and is still a fair size bigger then jadna.  In his hand he holds a small can of...whatever it was they left for them to eat, and offers it to Mars, so that if he wanted to throw it and get an idea how far away the wall was, he'd be able to.