Been digging something all my life and the only a couple of instants come to mind. Once digging for old bottle my brother and myself being youngsters created a tunnel over a bank along a country road. Car went past one day and the tunnel collapsed and we buried, my brother was in the upper part of the tunnel and was able extricate himself quickly and I was buried pretty bad. The only reason I'm here today was the fact I had the air space in around the body from being in a crouched position when it happened. It took a fair amount of digging to get my head exposed to the sunlight and a good 30 minutes to get the whole body out.
The only minor thing that has happened detecting was back in the mid seventies at a city hall where there was the granite war memorial on the front lawn. Well this drunk came up to us and expressed his displeasure of us digging up the graves of the fallen. We politely explained that there was in fact no fallen soldiers laying there, but he wasn't convinced. He stood by watching as I was digging a target and at the time we only used 12" screwdrivers for a retrieval method. I was keeping an eye on this fellow and sure enough he tried to kick me in the head, and the knee jerk response was I hit him full on in the chest with the screwdriver tip. Heard later from the EMS that it might of stopped his heart as he went down like a shot chicken flapping then was still. Police took the statement, witnesses came forward and explained that the guy tried to assault me and it was just a defensive move on my part. Drunk off to hospital with a purple herbie on the chest and a set of newly attached wrist jewellery provided by the police.