Glad he is okay. Anytime I need to remove a clamp I check the valves, then double check and make sure that the clamp I'm removing is the right one and that any valves associated are closed. Had a momentary lapse once when removing a line from the CIP arm on a fermenter. Forgot to close the valve on the CIP arm but did close the one on the line. As soon as that I opened that clamp I got showered with Iodophor, which is fortunate. From then on I always check and recheck.