I Took One to the Head Today

Glad you are okay. I had my "Come to Jesus" moment. While tethered, shooting a Disco, and I heard a huge "BANG"! Ears ringing, I looked around as I knew my finger was not on the trigger. Found it!

Only tether with high end micro-hoses. Holding high pressure for long periods of time are best left to cylinders.

Just received my tethering set-up today. Glad I 'popped' for the Huma hose when I picked out the components!😁
 
On some fill kits, you can add an air restrictor, to prevent a lose hose flying around like a whip. It probably won`t stop a hose jumping away if it get loose with full tank pressure, but it will make it stop jumping a couple seconds later. On my FX fill kit, the hole in the block, which face the scuba bottle, is threaded. So a screw with same dimension can be added, and the high pressure air has to move past the threads. So if I let the hose hang freely, and open the valve on the scuba tank, the hose does not fly around. It also prevents you filling the gun to fast. I usually wear safety glasses while filling the gun, just in case. Also if you recently have changed the O-ring on the foster connector, it sometimes require more force to push it on until the locking engage.