For some reason I had to do the 'A Guardian Rises' again. And now I am stuck at 'Schism'. I had to reload already, but it didn't help me. The first time I did this quest, I got the gun from the crate, but when I was shooting enemies, they regained their health or instantly respawned. They also weren't aware of my presence so they didn't shoot or fight back at all. Now I try to pick the gun from the crate, and it does nothing. I can't proceed.