I’ve seen an SCBA cylinder snapped off at the high pressure connection. It was strapped to the back of a fellow volunteer firefighter at the time.
We had responded to a report of a freight truck with a possible fire in the trailer. The truck was pulled over at a rural highway junction. It was early winter, just after sunrise, and the temp was around 20°F.
It was decided to ladder the rear of the trailer and send a firefighter up one ladder with a Halligan tool (an industrial strength wrecking bar) and another firefighter with a charged line up another ladder. First guy would knock a hole in the roof of the dry van (which was only slightly thicker than a beer can), second guy would knock down any fire.
While the ladders were being raised, one of the guys going up to the roof was waiting, wearing his SCBA, by the side of the trailer. A charged red line (1” hose carried on a hose reel on an engine) was layed out on the highway with the nozzle cracked to maintain circulation through the pump. The trickle of water was flowing across the road on the the shaded side of the trailer where the guy in the SCBA was waiting. He turned, stepped on the semi-frozen puddle and fell straight down on his ass. The neck of the bottle, where the high pressure line to the regulator is connected, was about level with his tailbone. The connection snapped off when he hit the pavement. You know how the coyote would spin around rapidly when the road runner went speeding past him? That’s exactly what the guy on the ground did. Spun around about 3 revolutions on his butt like a break dancer on speed.
Fortunately, there were no injuries, the fire turned out to be a case of restaurant soda cracker packets, which had gotten too close to the propane space heater used in cold weather in trailers carrying mixed freight, and was smoldering. And, we all learned what a 150lb guy wearing 30lbs of bunker gear and breathing apparatus does with a 2200psi bottle rocket strapped to his ass.