So when you start moving your train the doors auto lock, guess stopping you from jumping from a moving train. But if you open the door and give it power you can still jump from the train and let it go without a driver Hard to show with a screenshot so i did a recording of it.
Should be on a real train too? So the question is: why opening the door and jump out the train as the driver while it drives away? Would you do this in real live? No!
I'm not sure about this train specific, but in most trains is a foot-pedal for the driver which has to be pressed permanently or the emergency would kick in within a few seconds. Since the safetyfeatures are default-inactive you can do such things.. try it with all safetysystems enabled and see how far the train goes..