Superiors occasionally need to remind their subordinates what the plan is. Subordinates tend to get confused and lose track of the bigger picture, because they're usually focused on the details and on not getting beaten up by the heroes.
So it's perfectly justifiable to have the lackeys not quite clear on what it is their boss is trying to achieve - even if they've been told.
Commentary by memnarch (who has not seen the movie)
Ohhhhhhhh. Now there's a good reason for the mirror-shine floor; it's electrically reflective! No need to raise your arms up to zap someone if the floor will bounce the lightning where you want it to go! ........ That's most certainly not the actual reason the floor was made like that. But it's a neat visual all the same.
And Kylo once again shows himself to be a rather bratty kid. Seriously, he needs to learn some restraint or something. I know movie-Anakin had similar looking temper problems until getting stuck in the suit of armor. Maybe Snoke is hoping for something similar to happen? If it does, that'd fit reasonably well with the comment made last comic.
This whole bit is actually a pretty good way to get Kylo refocused on Snoke's goals too. Lost focus because the previous personal target died? Here's another one! And to add to it, the other players get to see this set-up as well. I wonder if these sessions are still being videoed? I can just imagine Sally turning in place to do the two different roles, waving her arms around as the Kylo side lunges then gets lightninged.
Transcript
Snoke: Find Luke. Retrieve the Jedi texts. Get the map to Ahch-To.
Kylo Ren: We need to crush the Resistance!
Snoke: That’s not on the list. Finding Luke is. Luke Amidala, son of Anakin.
Snoke: You do remember Anakin, don’t you? The boy who almost killed you.
Kylo Ren: It was an unfair fight. He was hopped up on midi-chlorians.
Snoke: I understand you goaded him.
Kylo Ren: He cheated in the pod race!
[SFX]: lunge! {Kylo leaps to his feet}
[SFX]: Kzrzzkk! {Snoke blasts Kylo Ren with a brief burst of Force Drain lightning}
Snoke: Don’t raise your voice at me, young man.
Snoke: You pathetic weakling. Anakin beat you then, and he holds power over you still.
Snoke: A lifetime of rage over a race. He drove you mad!