There should be a wooden crate in the room that has the gun case in and also other gear. However, this wooden crate doesn't always spawn. I'm assuming this is intentional. I've only had 2 spawn no crate out of 5 so far.

Surely they should all have them, there is only 3 out of 24 bunkers that get unlocked. Going to these high risk areas where others will be heading to not even find the intended loot seems daft if the risk reward system isnt balanced.

Honestly, it is such a reliable way to get high end loot so far for relatively little effort (compared to gathering an NBC kit and going into the gas zone) that I feel it'd be unbalanced to make the loot spawn in every single bunker. Opinion aside, I am curious to know whether or not this is supposed to happen.

Yeah the gas zone Wasnt great, other than the experience. Gives you a real sense of being in an infected area. I will keep grinding and seeing if I come across one.