I'm only a young mechanic been in the game for 6 years, i haven't seen too many strange or dangerous incidents. One thing i have seen were building maintenance staff using the elevator to move a safe from the top floor to the basement. The safe exceeded the payload, and when we got there, the car was firmly on the buffer, the car had drifted away from floor and sailed into the pit haha. They had to use a gas axe to cut the safe into small pieces to get it out and have the lift move again.
almost forgot after we repaired both cars and ran a new oil line, another contractor jackhammered a hole in the other hydro line.
We couldn't even walk in the secondary to rig the piece because the slightest movement would have let it loose. We had to fish a rope through it from the machine room floor and finally pulled it up.
Once I was walking accross a parking garage, looking at an elevator about 200 feet away. With the doors wide open, it took off at full speed, leaving the shaft exposed. Reminded me of a huge guilotine.
I ran and shut it off, closed all the doors.
Turns out, that the long, underground electrical run put about 80 volts of noise on the door lock input to the control. That version of MCE control could not distinguish between a genuine "doors locked" signal, and merely 80 volts of noise.
A 15 k ohm, 2 watt resistor, placed between the door lock input and ground, served to drain the noise from the input, but also not get hot when the door locks were genuinely made up.
Which makes me wonder this- Why are safety and door lock inputs designed with such high input impedance? Seems they should "test the waters", just a bit, by partially loading the input signal, to make sure it's not just noise. (Cars running full speed with their doors wide open is, ahem, unacceptable)