2m is about as close as two units are going to get, voluntarily. The collision prevention routines will kick in to stop them getting any closer.
Not much you can do about that except use setVelocity commands which, even combined with switchmoves, are not going to look very good in this circumstance. (And I've just had a sudden thought that setVelocity doesn't work with soldiers in contact with the ground ... not sure)
Remember that the player unit can run faster than AI units.