Very often during encounters, 1 of my players tends to go outside of the prepared combat grid. Its mostly the warlock of my party. I totally understand that he wants to stay away from trouble, but I seem to have trouble to "lure" him so he stays on the battle grid.
The end of the grid is not the end of the world, for example if my players fight in an open terrain (village, woods...) the ranged players simply run off. I already tried to change that by enlarging the battle grids, but still, the warlock goes wherever the squares stop... Sometimes he even refuses to go into a room, stands at the door and shoots in. The thing is I dont want to tell him "stay on the grid" but I would like his character to move inside because he wants to.
I'm offering cover, difficult terrain, different heights and everything on the terrain but still, it hardly works. I might also add here that he likes metagaming, thinking of every possibility and always maxing everything till the end, be it situations, his char, etc.
The tank is not the problem, the is on the front, the leader is usually also on the grid and so is the controller. But this warlock striker really gives me a headache.
You guys got any advice how I could make my player more "comfortable" on the battle grid?