recommended raiders :
- sooma with redeemer to defend against engineers.
- doldren, because he can sneak behind turrets.
- konstantin, he can easilly get rid of foes on bridges with his sphere.
- any character able to destroy turret's protections and large packs of ennemy quickly. rak for instance.
the first part of the mission is the hardest.
i think there is no mission where it is as CRUCIAL to end engineers quickly.
that's where sooma comes to play.
make her protect the valve from engineers and your mission is half won.
as tekato said, if you don't have sooma, or she is not smart enough or well equiped to protect the valves, then try to collect the more aleph before putting it. obviously engineers won't be able to steal aleph from the reactor since it will be empty and i will charge very fast once you all put your aleph it in. so you'll reach each tier quicker and more easilly.
yet be carefull often people with lot aleph becomes target for monsters and if you die, well, aleph will probably dies with you.
all the other parts are pieces of cake.
on part 2 and 3 doldren can sneak under turrets to activate the levers in a flash.
don't destroy turrets at the end of part 3, they will save your lives for the final rush.
final part, doldren can go directly to extraction point, so that if anyone dies, it will spawn there too.
et voilà. you have won.
finally, don't wait to much for extraction since, hordes of foe will spawn and surround the area once the extraction is available. and if your team mates are already gone, you'll maybe have trouble leaving the stage.
no big deal if you are not in sudden death mode, but if you are, it can brings to a failed mission (specially if you are left alone to face a konstantin antag who will keep the extraction point as his precious. believe me ;p )