Evulz puts Alice on a bus to reduce her interference. Bob is still allowed to call Alice though.
Justified: Bob was a former Mook of Evulz's who performed a Heel-Face Turn. Evulz is planning an extremely complex plan and Bob is necessary for a vital part of the plan. Since Alice actually was holding Bob back, her death is necessary for the plan to work.
Bob, a BadassBlood Knight whose hobby is fighting villains, kills the rest of Emperor Evulz's Five-Bad Band because he believes they were holding Evulz back.
Subverted: Evulz apparently kills Alice by shooting her. However, it turns out Alice was wearing a bulletproof vest, so she gets up and simply walks away after Evulz leaves.
Double Subverted: Evulz realizes Alice survived and kills her the next day.
Parodied: Evulz kills Alice, and Bob, so happy to finally be rid of that hateful woman, sends Evulz a thank you note and chocolates.
Zig Zagged: Evulz decides to have Alice killed by getting her shot by a sniper. However, the sniper turns out to be Bob and as a result doesn't fire at the last moment. Evulz, seeing all this, knocks Bob out, takes the rifle, and attempts to fire it. The rifle misfires, so Evulz takes a pistol out and shoots at Alice. He misses, so Evulz takes out a knife, charges at Alice, and attempts to strike her with it. He misses, so Evulz activates a C4, stick it onto Alice, and gets out of the area before it explodes...
Evulz doesn't even try to kill Alice.
Although it's common practice for Evulz to do this, Bob doesn't have any friends, so it wasn't necessary.
Enforced: Evulz is an Evil Mentor, and all of Bob's friends are good. They will not play nice.
Lampshaded: "Bob, your arch enemy has an obsession with making you a super competent loner. If you don't deal with him, I'm putting our relationship on hiatus."
Invoked: Bob has already performed a Face-Heel Turn, but Evulz can see he's still conflicted about his decision, so he arranges the assassination of Bob's former comrades to cut any ties he might have with his heroic past.
Exploited: Bob and friends fake their deaths so that Evulz lowers his guard before an ambush.
Defied: Evulz wants Bob to live up to his potential, but realizes targeting his friends won't win him over. So he just feeds Bob some Dark Side Donuts!
Discussed: "Why is it all my enemies think I'll be stronger as a loner?"