S1·E24 Thoma's Truth

Dumas and Thoma fight for Helga, but Dumas has the upper hand thanks to being superhuman. Undeterred, Thoma and co. head off to find Helga once more, but Thoma is strangely entranced when he discovers Tina's body in one of those giant cylinders. The sight of it brings back Thoma's repressed memories... Dumas finally defies Georca for once, and after being beaten Helga attempts to stand up for him to no avail. Finally they bond as brother and sister, and Helga beseeches him not to go through with his plan to kill Georca - however, Dumas knocks Helga out, and as Thoma is wracked with guilt over his past transgressions Dumas teleports outside the ship to finish his machinations...