help with reactor 09 gun scene (spoiler warning)

[The_Other_Guy]

Last try didn't work so hopefully someone answers this one. I can't figure out what to do with Matt at the gun scene.  I already exhausted all conversation options, tried combining every item with every other item, and tried using every item on Matt, Marson, and "thing" but nothing worked.  I also can't find anything else to interact with.  Someone please help.  BTW how do you hide text; I forget, it's been a while.

edit: Nevermind; someone did finally answer my previous post about where I was stuck but I'd still like to be reminded of how to hide text please.