There would have been a lot to better design this duty:
More intuitive mob AI: I have been dodging around mobs since Eureka, so that wasn't hard. It does suffer the same flaw where mobs don't have a set path (like the Thancred mission) or suffer from odd density. Stealth play is hard in a game that isn't designed for it, and not a lot was done in this case to make it feel more than "it's just hard". Didn't feel rewarded for ducking and weaving around spazzing ghouls.
The only other part of that sequence that broke it for me was the canister. It's on a magitek. That's great, but there are quite a few of those and the one you need is back down the path you came. You.. should probably already have the idea to pick up the fuel because of what we saw earlier in the MSQ. You should be able to pick it up because it would be useful, just like how you can freely pick up the med kits. Everything else felt fine, imho.