That sounds like they were at the secondary ferment/carbonating stage and have either mixed up their sugar ratios, or bottled too early and got a bottle bomb. You really need to leave the beer until you get stable readings for at least 3 days. Yeast can stall and then surprise, your hard work has ended up on the walls and not in your belly. Hopefully that didn't stop them and they refined their processes. It's a great little hobby with mostly delicious rewards.That looks pretty cool! I had friends that pressure fermented (without fancy tools though), but they always forgot about them until one of the bottles finally exploded. Oops, haha.