Not only is Mr. Milchick someone who will carry out exactly the agenda that Lumon and/or the Eagan family and/or Ms. Cobel tell him to, but he'll do it because he's desperate to climb a corporate ladder.
"[4] Erin Qualey of Vulture wrote, "The way Tillman makes Milchick’s face go slack when he’s displeased, like he’s transforming into a robotic mercenary, is chilling to behold.
[...] He never raises his voice or resorts to violence (that we’ve seen onscreen), but we can tell he’s deep into the cult Kool-Aid and is ready to do absolutely anything to serve Kier and the Eagan family.
"[5] Jeffrey Speicher of Collider commented, "Milchick can look Mark, Helly, and the crew in the eyes while flashing that 1,000-megawatt smile and telling them what they want to hear when you know, in his mind, that he is scheming to keep the quartet squarely under his thumb.
If you've ever read Machiavelli's seminal work The Prince, you would know that Milchick keeps his employees happy enough so he can continue to rule without impediment, just like the Italian philosopher noted.