If it's things we've had to do (as opposed to things we chose to do) then one of my Foundry experiences is up there,
We had a tilting Furnace that held about 1/2 a ton of molten Brass, looked something like this,
It ran on 'fuel oil' but was lit initially by Calorgas propane from one of those big (48kg?) orange bottles with a reinforced plastic tube connecting it to the burner head which over the years had been slowly shortened as metal droplets had melted the section where it entered the burner.
One day shortly before a 'pour' the crucible cracked and not just a small crack but a catastrophic failure which dumped the whole contents onto the floor and the 4ft tall gas bottle was stood next to the blower fan in about 3 inches of molten Brass. There were only two of us in full safety kit at the time so me and the furnaceman had to rush in and 'rescue' the cylinder, luckily nearby was a 45gallon waterbarrel that we could dump it in before heading out the door pretty rapidly.
Took a while for the heart-rate to return to normal after that.