Weirdly that's the exact same mission where I first used the pump-action with slug ammo... after reading about it on here. Stayed in cover at the end and they just kept coming in waves... I was gutted I couldn't go back and loot everyone afterwards, I'd have made a fortune!
Hours in and still on Chapter 2, made some story progress though and unlocked the pump action shotgun, and holy moly this thing is a lot of fun
Doing a mission where your allies are encouraging you to use a moving wagon as cover and I'm running around like the Doom Marine