@Midnight9746 Ok, yeah. You'd need some way to start and stop the sequence (like recording and looping a clip), and that might mean introducing some new device or UI to the game.
You could use the waypoint UI, if all you wanted to do was place a start and stop point, i.e.: You activate the dummy, run to where you want the sequence to start, place the first point, do the sequence (it starts recording when you start moving), place the last point, shoot at the DUMMIE.
From a dev perspective, it wouldn't be difficult to buffer and loop a few seconds of player input. It would also be an inherently stable approach, as players-controlling-characters is a core feature of the game.