I've had a similar dream a few months back. I keep a loaded 12 ga. in the corner of my bedroom, chamber empty and safety on as a default, but when i need it, i just pick it up, pump it and press the safety button and it's ready to go.
Anyway, i had a dream one night that there was an intruder in my apartment, and i needed the 12 ga. I picked it up, pumped it, and headed out to face the threat, and i dont quite remember exactly, but even though i knew in my dream what to do with the gun, i couldn't do it. I either started fiddling with the safety, or maybe i just couldn't pump it, or whatever, i don't know. Anyhow, i couldn't bring the shotgun to service when i needed it.
I know in real life, once i grabbed the shotgun, it would be ready to fire in a second, but in my dream, it just didn't work that way. I thought about it the next morning and it frustrated me. The only thing i could think of was that sometimes i think about scenerio's in my head and worry that i might not be prepared enough. I think i worry too much that when the time comes, that i will be too nervous, or have a brain fart, or draw a blank when i need to arm myself and use my weapon. That's what it was for me, anyway.