With the Hab disassembled, Mark feels the full weight of his isolation. Although he knows that he's beginning the final leg of his journey (whether he survives or not), he still can't help but feel unsettled. To be honest, we'd suggest throwing some disco on the stereo and blaring it to high heavens. Rovers have good sound systems, right?

Mark's fears are amplified by the fact that he's completely and utterly alone. As every horror movie ever has shown us, isolation has a way of stoking the fires of fear. Of course, Mark has a pretty low chance of running into a deranged serial killer on Mars, so maybe it's a net positive.