In general, the enemies aren't all that strong or accurate.
This is a simple 'survival' mission where enemy troops come different directions all around you. I found a real easy mission for this is Operation 1, Mission 6. 'Death from Above' asks you to kill 3 enemies with a single airstrike. Usually you should stay a bit ahead of them just in case enemies spawn to kill them. Getting away and protecting the prisoners can be a pain. Just remember to pick up the repair boxes as you go along and you should easily finish the level Take your time to avoid needing to worrying about dying/failure
