Not sure, risk of making bodily contact with the mechanism, I think.
There is not much open mechanism there, just a slit into the wall for the support pin.
Pretty common prank to scare regular people was to ride there, make there a hand stand and then pretend to the people outside the cab had flipped over there...
But I dont think Paternoster is in any way more dangerous than any other similar constantly running device (like escalators, moving walkway,...; assume all the safety equipment is installed and all machinery properly maintained). It may look scary, but if you are at least a bit physically capable, it is quite easy to "grab the concept" and enjoy the advantages it has (mainly no waitinh time for the people and high throughput at relatively low power consumption for the operator).
Of course, people with limited movement ability can not use it, but their main point is to take over the majority of the crowd (it has way higher crowd throughput capacity at very low energy consumption) and so free up the classical elevators for those that really need those (less able, with luggage, small kids,...).
The "low energy consumption" is not an error in any way, although it may look like they consume a lot of power while moving all the time. The point is, Paternosters are intended as part of an elevator system (together with one or two shafts with a classic elevator), to take over the majority of the crowd transport during peak hours (and switched off all other time). Because the mechanism is moving at constant speed, the propulsion system could be easily made way more efficient than with an elevator that needs to repetitively accelerate and stop. When there are large crowds constantly moving, the consumption is barely half towards the modern, high efficiency elevators, when compared with the same transport capacity. Of course letting it run when no or only minimum people are traveling is a waste of power, but that is not what the thing is intended for.
Plus it occupies rather small floor space for the shafts.