Shortly after Miltia, the boys are brought to a Federation space station. They are separated before arrival, which pisses off Rubedo something awful. Helmer is called to smooth things over and learns some of the unsavory sides of the Yuriev Institute.
When it comes to notes on this, I went on reddit to see if I could find the industry term for disposing of lab animals and I saw "saccing" used a lot. So that is what Rubedo is referencing. I assumed Yuriev would refer to terminating URTVs in the same way.
Also Rubedo is very much aware of how little his authority as link master matters to anyone who isn't a URTV. But it is the only card he can think of that would give him any authority, so maybe if he's forceful enough it'll work. He really does think there is a real possibility that Albedo (to his panicked mind, his brother is not completely invisible) and Nigredo would be killed for being defective now. I imagined tons of standards meeting that fate for injures that didn't heal right and UDO exposure.