It's not hard to come up with tasks that inherently cause widespread death regardless of the skill of those who carry them out. Starting fairly large and heavy objects moving at considerable speed in the vicinity of other such objects and pedestrians, cyclists and stationary humans may just be one such task. That is, the inherent risks (i.e. you cannot stop these things instantly, or make them change direction instantly) combines with the cognitive/computational complexity of evaluating the context to create a task that can never be done without significant fatalities, regardless of who/what tries to perform it.
It's not hard to come up with tasks that inherently cause widespread death regardless of the skill of those who carry them out. Starting fairly large and heavy objects moving at considerable speed in the vicinity of other such objects and pedestrians, cyclists and stationary humans may just be one such task. That is, the inherent risks (i.e. you cannot stop these things instantly, or make them change direction instantly) combines with the cognitive/computational complexity of evaluating the context to create a task that can never be done without significant fatalities, regardless of who/what tries to perform it.