Many years ago 4 ops who were staying in shared accommodation in Brighton went out on the piss on a Thursday night (a common tunnelling thing as Fridays are normally shorter shifts). Strangely they did not turn up on Friday. I say strangely because the rules are quite clear and, at that time, a level of morning pissedness on a Friday was deemed acceptable if it was your turn to work the weekend. Anyhoo, the no show caused quite a few problems for the TBM team and there was much swearing and vile hatred retribution planned.
At around 11:00 a police car showed up at the site and I along with the Project Manager took the police to the meeting room where they proceeded to tell us that the 4 lads had been involved in a car crash, no other vehicles involved but one of the occupants of the car had died at the scene.
Turned out that they had woken up late, fired into a car, sped through the centre of Brighton and the driver lost it on a 90 degree bend. In the back seat were Glen (surface foreman) and his childhood (best) friend Nick (back up op). When the driver lost it the car hit a tree and decapitated Nick. One of the hardest conversations I have ever had was Glen telling me that, when he regained consciousness, he vomited on Nick's head that was sitting on his lap.
TL:DR
There is always a reason why people do stuff. But sometimes you will never know why.