Insane part with the 2 Troikas on top?

There is an easy way to deal with it although it is not truly 100% confirmed that you will pass that area, you will still need to give it a few tries but then the general strategy is there.

From where you come up after the ladder, there will be two Troikas, the left and the right. It would be better to grab the Troika at the right instead of the left one. Somehow, the left one seems prone to getting shot at And just target those that are approaching the ones on the right, forget about the left ones unless you have some free time to spare (no enemies on the right) .

Hopefully this helps, i have tried about 3x to complete it. Having another person at the troika next to you wont be a good thing as insane mode, you die immensely fast and you might have to bother with the other person too, and just in case if you dont know, you cant revive shots from torque bows.... so your percentage of getting killed and restart is double the chance, however this is offset by the number of enemies since there is 2 troika on the move...