How would one train Reflextion skill on a Rogue with maxed Stealth (+10 AC)?

The game seems to make enemies ignore a stealthed character that passed the Stealth check.

I would assume, if you had a Fighter and Rogue up front, and the Rogue passes the Stealth check, the Fighter would be hit (this usually happens around 80-90% of the time).

I have noticed that, even with maxed Stealth, my Rogue still gets hit often enough to matter (I usually buff him with Guardian Angel).

My question is, if my Rogue was standing alone on the front lines, out in the open, against melee only enemies, and the Stealth check passed, would the enemies then run to attack the flank characters? Or would they stand there dumbfounded? Or would they retreat?

Better yet, if you can funnel your enemies so that they can attack only the front line. If only the Rogue is there, and he passes the Stealth check, then what? They stand there, or retreat?

I dont know for sure whether they will move from the stealth characters to the side,
as i hardly train in the open, but when i did(20++ times?)
i never saw them move to another character/quadrant of the formation.

What i can say for sure they may start to retreat
after failing at least 2 times to look through the steath skill of the character,
but this appears to apply only to the ones that are directly involved, not those in 2nd line who cant atack.
This leads to me usually going for a crevasse/bottleneck where they can only attack one quadrant, or 2,
that way the ones in 2nd and 3rd line will block the ones in front that actually want to retreat.
(keep in mind if the group leaderdecides to retreat, he may "convince" all to do so)

The imo best monster to train stealth is the forest mite,
as their attack cycle is quite short,
and last not least they need so little space that 3 can attack a single quadrant.
(also gives 3 chances that one of them looks through stealth, so they do not start to retreat)
The forest mites are a random spawn (at least) on Arnika Trynton Road.
The 2 groups in the cave at Arnika Road have an excellent crevasse nearby,
outside the cave, left to the entrance, its not that hard to lure them to the spot.
Ofc youre locked in, if you want to interupt training use terror followed by sleep or freeze flesh

Note:
The omnipotential supernatural entities of crpg, like eg. His Holiness The Flying Spaghetti Monster,
will consider everybody so evil that he/she/it kills his most effective trainers,
as allies of its archenemy The Evil Pizza Diavolo, and send his cyberdragon to trigger bsods on their devices.

It's funny that you bring that up. In the worst (best?) case senario, you are surrounded by 4 Savant Slashers in Arnika. By moving, the Slashers just stand there, dumbfounded, that you moved (they won't attack the new target you presented in front of them for another round). This happened with my last party, when I had physically weaker characters (the Bard, Gadgeteer, and Priest were it).

This is assuming that you didn't kill all set enemies before Arnika.

I am going to answer my own question, and assume that they will retreat if the Rogue is the only option presented to them, and passes the Stealth check. By having a Fighter up front with the Rogue, the Fighter serves as a meat-shield, attracting the enemies to attack him (while the Rogue only gets attacked 10-20% of the time).

This method, while surely slower, will guarantee that enemies will not retreat. Your Rogue will still be able to train their defensive skills (Shield, Iron Skin, Reflextion), but at a much slower rate.