Some frequently asked questions regarding out of formation that I gathered.
Q1) Are they fleeing?
A1) They only flee if they failed their Cmd check for being out of formation at the end their activation. They take this check at -2 CMD.
Q2) Can they engage an enemy model?
A2) Fleeing or being out of formation does not impair a model's ability to engage. So, yes.
Q3) If those 2 grunts come into contact with a model that causes terror, do you roll your cmd check based on the grunt or based on majority of the unit?
A3) Terror checks are taken on a unit level (This also means that you don't suffer the -2 Cmd for this check).
Q4) If those 2 grunts come into contact with a model that causes terror and fails its cmd check, does the whole unit flee?
A4) See above. Either the whole unit fails or none of them.
Q5) If those 2 grunts started their activation as out of formation, fleeing, and have an enemy between them and the leader, where do they run? Out of Formation rules says that you have to run directly towards the leader (or advance towards the leader) but fleeing states that you cannot advance towards an enemy model...
A5) You're stuck. One rule requires you to move in a certain direction, while another prevents you from doing that. Advance 0".
Subject: Out of Formation FAQ 