Wish Upon a Star Episode 8

The Yamato falls into a dimensional rift and finds itself unable to escape. A Gamilan ship that is also trapped there approaches the Yamato and both crews come to a temporary ceasefire while they work together to escape. After the Yamato escapes the dimensional rift, General Goer meets it with a Gamilan fleet. Instead of fighting the fleet, the Yamato runs away, and the dimensional rift temporarily widens, swallowing the fleet.