When Corran Horn in his cover role as Jenos Idanian infiltrated the Survivors in the quest to find his wife Mirax, Timmser was one of his wingmates within Rock Squadron. She was adept at piloting and proved to be an aggressive flier; though she was known to be quite assertive among her fellow pilots and raiders, she was nonetheless thought of by Corran to have had potential to be a better person. During his time on Courkrus, the two became friends. When Corran was promoted to leader of Bolt Squadron at Admiral Tavira's insistence, Timmser replaced him as leader of Rock Squadron.
When Corran's other alias—the mysterious "Ghost Jedi"—began making its presence felt among the Aviary, Timmser, along with Caet Shrovl, fled the planet in a pair of tri-fighters that had been outfitted with salvaged hyperdrives.