Agreed, this mission is HELL. Not only the first part, but even the second part, there's just all kinds of crap going on, missiles, bullets, silent elites that grab or snipe you, exploding flowers, etc....
Oh and Schneider's hitbox on his mech attacks are completely unclear. As a Dark Souls and Let It Die veteran, I am used to clear, concise, easy to see hitboxes that match up with the 3D mesh of the object attacking me. If I am in front of Schneider, his sword swing attack hits everything in the general area of "in front of Schneider". Rolling does not save me, moving forward or backward. I am clearly not coming into contact with any part of his attack, but it still hits. Same for his stomps, which have like 5-10 meters of completely invisible AOE, but they don't hurt as much and are easier to avoid.