Slitherine

Ok, just got this and I got a bit annoyed by it. I had 2 marine units in diferent locations to attack a xeno clone, I didn´t have enough moves to do it so they would attack in the next turn, but one of them destroyed the xeno AND the other one to the exact same place the xeno clone was and got killed by friendly fire! I wasted a unit.

That's unfortunate. I don't believe this sort of friendly fire should happen, but I haven't had it happen to me. I tend to cancel orders (select a unit, then right click on its current territory) if they can't make it to their target's destination in the same turn. That might help you.

I have had similar situations, but I have never had this happen, where one of my units moved in and the other attacked it. They both just moved into the hex.