End game difficulty

My favorite class is the Gunner and I like using the lead storm with the over clock that you can't move.

I'm struggling to navigate terrain and get to haz 5 so movement I need to work on also I was wondering if anyone had suggestions on something I could have done differently or a thought for next time if I'm in the same situation of this story...

I was on a ice map high up one way in one way out at the end of the cave there is a big drop straight down and the opposite end there is a very steep slope you basically had to jump up to get to the top this was near the end of the mission and I never made it out.

Is there any thought or advice on what I could have done in that mission to get out alive and please if you want to include what you could have done with a different gun don't be afraid to use that.

Thank you in advance.