This is Chapter 39 of Who Brought the Steak Tartare?, you may want to go back to Chapter 38 or start at the beginning.

39

In the quiet hours after they had all eaten, while most of the crew was sleeping, Back eased himself out of his room and into the corridor. He waited, listening, before gliding to Akaitcho’s door. Back slid the door open, and drifted into the chamber. He closed the door behind him. The chamber smelled strongly of urine. As he turned to face the man in the bunk, he was startled to find Akaitcho’s eyes open, gazing at him.
‘Is it time to eat again, Juana?’ he asked.
Back didn’t answer, hoping to keep Akaitcho’s delusion going as long as possible. He surveyed the scrawny figure strapped into the bunk. Akaitcho’s skin no longer hid the truth of his bones. His eyes stared out of his skull without finding or even seeking Back. This dreadful future predicted by Akaitcho spurred Back into action.
He clapped one hand over Akaitcho’s mouth and pinched his nose shut with the other. The old man was so feeble, he barely struggled. Akaitcho did not even succeed in releasing his sleep straps.
Once he was sure that Akaitcho was dead, Back used his knife to puncture the artery in the old man’s neck. He quickly placed his mouth over the cut and began to suck. Back sucked the warm blood out of Akaitcho until it seemed like there was no more left. When he was finished, Back placed a bit of medical tape, which he had removed from the medical cabinet, over the cut.
He released the body from the bunk and pulled it over to the door. Back poked his head out the door, into the corridor. It was empty. Towing Akaitcho’s body behind him, he made his way to the bathroom where he opened the door and pushed Akaitcho in, following after. Back unbuttoned Akaitcho’s pants and reached in, fishing around for his desiccated penis. He pulled it out and used his knife to cut Akaitcho before hooking him up to the urinal funnel. Making sure the fit was snug, he turned on the vacuum pressure and left the bathroom. Back returned to his bunk and once again slept well.
Chapter 40 tomorrow, same time, same place.