File this under ? *** Spoiler Alert ***

I've always noticed what you're talking about, but while superficially there appears to be an unwarranted (if extremely brief) delay between "Fire!" and the wheels of the lift making contact with the wires (thereby setting off the explosion), I think it shows something closer to their being simultaneous events. Obviously that's the intention, but I think they do pull it off.

There are a number of goofs in this film (like you, I've been watching it since the 1960s -- saw it as a kid when it came out in 1961) but I'm not sure this quite counts as one. I see your point and it's crossed my mind but on reflection, personally, I don't consider it a goof.

But if you do try to file it, it sounds like it'd be one for the generic "miscellaneous" file.

Just because they were loaded and ready to fire does not mean that they were not operating the lift to prep for the next reload. I see it as him yelling fire just as the lift, which was heading down to bring up another shot, made contact preempting th final shot from being completed. Not a goof in my opinion.

The shells were on the lower level for a reason. Perhaps as a precaution they didn't want idle shells in the same vicinity as the guns as they were firing. Therefore the guns are loaded, the lift goes down to collect the next two shells, guns fire the next two shells are loaded onto the lift, guns are reloaded and the whole process starts again.

If you dip your foot into a pool of piranhas don't cry when you lose a toe!😞🐟