Question from latest episode - Irving/Mark/Helly

In S2E1, Mark refuses to work until the original MDR team is restored - which they are. In this past episode, Helena is told Helly has to return to severed floor, even with significant threats to her safety, because Lumon can’t risk Mark not finishing Cold Harbor.

Why doesn’t Mark refuse to work until Irving is reinstated? I get being pissed at the Helena betrayal and feeling hopeless about their position within Lumon but why just accept Irving is gone forever without putting up a fight? The only one from the team that pushed back was Dylan but then Milchick hinted at rescinding his privileges so he backed off.

I thought Mark would have done something more, especially since he faced the existential threat of non-existence when Milchick put him into the elevator in the first episode this season. Just seems sad that they’d let Irv go out like that, especially when Mark knows he could potentially bring him back because he did once before.