Rando was held captive by the spirit, so he needed medical aid quite often. But only Melanie could tell that he was really sick, the spirit gave him supernatural abilities to get political with the monsters that lied ahead. See all this while Rando was only dying at the hands of the monsters, and it didnt matter to him whether he lived or died. He just was so possessed by the spirit, that it would not let him go. Melanie only blamed him for all bad luck she was facing here. Rando couldn’t live like this with Melanie, so they parted ways, otherwise they would have to fight. The spirit was only staying arrogant and delibitating on Rando. He knew this torture could never really end, he was tied up with the others for life. So he needed medical assistance quite often, which only Melanie could deliver. It was never a straight route to the sick bay, and furthermore never a straight treatment for him either. Once Melanie got Rando inside, the computers handled the treatment. Only getting there on time, keeping the computers warm was required. But this was tricky and periodic. Melanie stayed fit there of. And was able to perform these tasks well enough for Rando to survive the others. But Randos judgement was erred and capricious, so was he consumed by them.