Tal'kasha revive mechanic

So today I learned that you can actually de-spawn mobs during the Tal'kasha encounter (boss). 

You kill an enemy, and then make Tal'kasha end her turn on it to get a "1" state. Then, if you kill that enemy you just killed again, move another enemy where they died, it will only ressuret the enemy that Tal'kasha got her state from.

I don't know if this is the only way you can do this. Can you go on there yourself? Use a summon? Move Tal'Kasha on the tile on the same turn it dies? Idk.

I just found this interesting as a popular guide site doesn't mention this anywhere, and I never saw it in a video until recently.