The AI movement routines are... really lethal in combat. Typically, they seem to "see" obstructions in their paths that simply are not present and will then either become stuck or decide to go alllllll the way around the block (into areas not cleared by allies) and promptly get shot. They decide to stay put on a corner.
It doesn't matter what orders you give them, for instance telling your medic to move to a point behind him before moving him forward (to try to change his pathing decision), they just suddenly decide to not walk through the open ground in front of them. I've had them go around the block, go into a house's upper floor and then jump out the balcony, all sorts of things, but walk down the open stretch of pavement in front of them to where I'm ordering them to go. {F22272} {F22273}