Heh. To me this sounds like one of those dreams that isn't the subconscious working something out, but just having fun. It's obvious you either like or have recently seen Japanese monster or science fiction films, or played games with an intrigue/shooter theme. I've had dreams like this myself. It happens rarely, but for no apparent reason one gets a plot that could be out of an action movie. Or, as you say, it could be your imagination bubbling away with plot material.