Is it possible to counter the "Hit and Run" tactic used by the Dungeon faction?

1) when Stalkers move to an adjacent cell with your Warrior, or you encounter them with a creature while moving.
2) it attacks; Major even provided examples.
3) nothing good will happen; the hero will lose and go to the tavern. Maybe it will appear again sometime, if the enemy doesn't buy it before you.

Vikh, you handled the Orcs well. It can be simpler: Trappers cannot place a trap where Stalkers are standing. So, revealing their location is very easy. Then, just stand next to them, attack, and kill them.