I have played extensively on Insane mode. Slaying Ravana I only survived (in an Ursa, no less) by circling around the Ravana far out of weapon range. I let the Sobek deal with it while telling bomber friendlies to engage (and fighter friendlies to protect my ass). Overall, the Ravana isn't a threat if you stay a few KM away. Not really the point of being a bomber then though. I've been killed by AAA's a few times before reverting to the "run and hide!" tactic. Besides that, stay away from the back side of the Sobek. Waiting 1km off and away from the Ravana nearly ensures survival. Oh, and if you dare be close to it as it goes off, you ought to have high hull and good timing. Riding the shockwave is a good way to avoid being killed at the last second by fighters.