Cave's corners hide enemies, while blocking movement.
In the image attached, the gal attempts to walk past a hiding corner, bumping into an enemy, and stops.
I'm not sure if a ranged weapon (e.g. gun) will allow her to shoot, but it doesn't allow a melee weapon, as 'there's nobody there'.
In addition, if you gain sight on the enemy (in this case, coming from the other side to gain vision), the gal will still be unable to attack them.
Expected: if attempting to enter a tile is force-blocked by an enemy, the movement should stop, the enemy be shown, and could be attacked as normal.