Onquanii meets with Voyager and tells Captain Janeway everything he knows about the Series-5 TAU weapon. He offers to use his advanced transporter systems to beam the missile off of Voyager whilst dampening its systems at the same time, giving his crew time to disarm it. In exchange for his services, Onquanii wants the weapon itself, claiming that he wants to take it apart and sell off its individual components. Captain Janeway refuses to let Onquanii have the weapon's power matrix since it could be used to deploy the weapon, but Onquanii is intent on taking the device in its entirety.
After failing to strike a bargain with Captain Janeway, Onquanii returns to his ship and then promptly opens fire on Voyager and attempts to transport the warhead off. However, the weapon sent a feedback surge through the transporter beam that destroyed the vessel, killing Onquanii and his whole crew.