I don't wanna be an ass, but the first part of the mission is actually fairly easy. Since the subs lock onto one seal and ignores the others, you can bait a sub with one seal while run away with another. How I do it:
-Assign a number to each seal (1,2,3) to micro better
-Use one seal (lets say seal no1) and place him in an area near where ONE sub is to bait it
-Once the sub that is baited attacks, run away with seal no1
-Use another seal (lets say seal no2 in this case) that was behind seal no1 to c4 that sub u just baited. The sub will continue pursuing seal no1 until the c4 blows up
-The sub should now switch targets and pursue seal no2 instead of seal no1. Seal no2 should now run away, while another seal (either sealno1 or no3) should c4 it.
-Repeat this hit and run process until the sub dies (I think it takes 2-3 c4s to kill one sub)
If done correctly, only the seal u used to initially bait the sub should take damage. I still dunno how to kill the conscript on the bridge, I just simply avoid it by killing the subs away from the bridge. With this strategy I almost never lose a seal, even on mental. However, its hard to execute this perfectly as u might accidently bait two subs at one. If that happens, focus on killing one sub with one seal ASAP and bait the other one with ur remaining two seals. Also, obviously don't bait a sub with a critically damaged seal.
I personally found the part where u need to reach the field bureau the hardest, especially on mental where u can easily lose something to a desolator. Though this only happens during mental, nasty things can happen when u get jumped by a paradrop, and a desolator is one of the paratroopers.
Edited by GoodGame1324, 25 December 2017 - 07:17 PM.