I sort of managed a near death experience. Not actually life threatening but it was a good show. Basically same lab, trying to boil different clear liquids out of a solution. You do it once and record the plateaus, then do it again and switch tubes at each plateau to separate them. Well we started heating it the second time and it hit the first boiling temperature, but nothing was appearing in the condensing tube. It stayed that way for a minute or so, then the temp started going up past the first boiling point with nothing having actually boiled out. I turned to ask my teacher wtf was going on, then the rubber top with the tube in it exploded off the test tube and the resulting spray of gas/mist caught fire and created a huge fireball.