its pretty hard to blow the cocking noid on an e-cocker. they vent at 90psi to keep that from happening....but yea screwing the lpr in raises the pressure so its just venting.
the guy is a tard though
lpr being that high is probably what blew the hose too.
heres how you tune it. set the lpr just high enough so the bolt clears the breach, then about 1/4 turn more for reliabilities sake. the lpr on a cocker doesnt work like on a timmy/ego, it just moves the bolt back and forth to cock the gun, it doesnt affect velocity.
for sweetspotting the hpr and springs theres a good guide on custom cockers or probably in the stickies here. its not hard to do at all, just need a little paint and a chrono. the general sweetspot is with the ivg about 2 threads in and then just adjust the hpr to the desired fps.
might have to adjust the lpr afterwards if hes got the ivg cranked in all the way too. if it is youd need a pretty high lpr setting to overcome the spring tension. again it just needs to be high enough to cock the gun reliably.
they are pretty solid, robust guns though. unless you physically break something off or damage it its pretty hard to mess one up.