Before
I don't see that anyone has mentioned this yet but you may notice she touched the black knob with her left hand within a second of the video starting. I used to work with trains (this isn't a train, it's a tram but I assume they have a similar system) and if the driver doesn't make any input for a certain amount of time it gives a warning and of there is still no response it automatically applies the brakes. The input can be anything, a brake application, a quick toot of the horn, windscreen wipers etc. It's to make sure the driver is alive and passing attention. Clearly this is not a perfect system as it can be overridden by touching random things without actually paying attention.
After
I see no one has commented on this yet. But I realized that you press the black button on your left hand at the beginning of the movie. I’ve worked on trains before (trains, not tracks that can be in the same direction) and if the driver hasn’t been on for a long time, he’s alerted and still responds to real holes. Brake lever, accelerator bag transfers, etc. Of course, this is not the right way. Because it can be done quickly without having to look.