The "Mob" API has exactly one public method: start(). It doesn't return. You can't be sure if it worked. And, most importantly, you don't have the ability to

The "Mob" API has exactly one public method: start(). It doesn't return. You can't be sure if it worked. And, most importantly, you don't have the ability to say "no, no, it started against the wrong person" or "okay, that's enough." It will run at its own speed, maybe finding a new target when the first one is destroyed.