Good Mixing!
The flash was very well executed... so not the inevitable question must be asked. Were/are you in a drum line? As that whole thing minus the sirens sounded a lot like a cadence.
It was awesome, I enjoy it. Different things are always welcome! Also you might want to look into writing a few cadences and seeing if a marching band would buy them off of you. Might not be a lot, but it would be neat to hear your cadence on DCI or something.
Keep up the good work.