Why Were We Here? - S5.E23

Official Ending - Tex reasons that ruling the Aliens would win the war. Church, arguing O'Malley can't be trusted in a deal, begins broadcasting on an open channel to prevent O'Malley from jumping into Tex. As Tex kills the last remaining Wyoming, O'Malley accidentally infects Simmons. Tex knocks Simmons out, and follows O'Malley into Caboose's mind. Church approaches the Reds and warns them to disable the ship so that O'Malley can't escape, before entering Caboose as well.

Inside Caboose's mind, Church finds Tex and O'Malley negotiating their deal to rule the Aliens. He kills them both, causing them to leave Caboose's mind. After killing himself, Church emerges from Caboose's head to find that in the interim Tex has taken the sword, while Junior and the New Alien have boarded the ship.

O'Malley then infects Donut. Tex then knocks him out forcing O'Malley to jump to a different host. After jumping to multiple hosts, O'Malley jumps back into Tex and boards the ship to escape. However, Sarge has placed Andy on board, and gives the order to detonate. The ship disappears, followed soon by an explosion.

Official Ending - Alarm

The Blues retreat to their base. Some time later, the teams loosely echo each other's episode 1 dialog, before Sarge calls the Reds to name a new ATV he built.