I'm satisfied the only way those extinguishers are going to go ballistic is if the Kaon roof shelf completely separates from the body of the vehicle - and I don't believe that could happen. Even then, I believe the extinguishers would still be attached to the shelf.
Advertising blurb for the holders:
Introducing the highest quality, most thought out Fire Extinguisher holder in existence. You could settle for a cheap Chinese holder that comes in black only with a tiny piece of 1" hook and loop that you pray is stitched on and won't fall off...or you could get ours, which is proudly Made in the U.S.A. - Did we mention, you have your choice of colors for no extra charge? That's right! Match your Fire Extinguisher Holder to the color of your vehicle, and/or any Bartact or Trek Armor seat covers and accessories. This fits both padded and non-padded roll bars, AND PALS webbing as a MOLLE accessory...so no matter how you roll, you're covered!
Here's a link to a video by the manufacturer:
FYI - for my installation, after slipping off the retaining loop, the extinguishers slide out the back (with some resistance) without having to release the large velcro straps.
HTH