I mean, I know they are choreographed; that’s not the issue. The question here is specifically about not killing the Sappers ahead of time so you can get the ‘complete’ fight, so to speak. When you have rockslides on consecutive turns or even two on the same turn, it’s nigh impossible to avoid getting hit (sometimes literally).
But with a sapper also appearing every stage, that frequency doubles and that can be a real problem.