I have progressed in this quest until I am in the cave and have to collect 5 explosives. I’ve gotten 4, but the 5th one seems to be stuck in a spot that I can’t reach. I need the explosives to get through a door, and the only way to get to that last explosive, it seems, would be to get through that door. Thus, I cannot finish this quest.
EDIT: Well, I found the last one. I believe it wasn’t spawning. The other one I saw turned out to be an ECHO recording.