After 426 is "demoted," the final remaining technician is put in charge of Zin's asteroid. 427 is the least threatening bad guy ever. Cool Samurai-esque armor or not he's still just an old gray-haired pensioner with bifocals and a beard.
Like 426 before him, he visibly does not like the idea of being the one Zin heaps all the responsibilities on. Sure enough, he meets his end not long after. And here we see Zin just uses his button-pushers as scapegoats for every single little thing that goes wrong. In 427's case, he is blamed for the escape of Doctors Quest and Belage, despite not even being present when it occurred.
Held by two Hymenoptoids, he insists, "This isn't fair! I wasn't in charge of watching Quest! Your bugs were responsible for guarding him! It's not my fault he escaped!"
Dr. Zin's reply to this perfectly logical argument? A pun. "Your number... is up!"
With that, the Hymenoptoids hurl the geriatric technician into a big glass cylinder which then shuts on him. Even as he gets to his feet and pounds uselessly on the glass, Zin pushes a button and flash-freezes 427 with a cloud of gas, telling him, "Your argument leaves me... cold." The door opens again and 427, now a human popsicle, promptly falls out and shatters on the floor. Having disposed of the perfectly innocent underling, Zin then tells the insects, the ones who actually failed him (!), "It would appear you are the only ones I can trust, my loyal friends."