Ice breaker makes short work of the tank if you fire on it from the platform above the door where you first enter that area. The tank can't hit you and it always stays in view. You are so far away that it won't even launch rockets at you. The crate spot is good, and there is also a hole on the other side of Valus' door that's a bit easier to get into/out of. That being said, I'm def trying this when I get home.