And "going off" - well, that's just the meaning of the phrase, right? Doesn't have much to do with "on/off", just that it changes in state. When a bomb goes off, it explodes - before then it was doing nothing. When a man goes off, he shows his temper - before then he was being calm. And so.
Also confusing I find the use of the word "ride".
So do I ride or drive a skateboard? Oh, right, we take the cheap option and "skateboard". Let me just train home.if something is a one-person mechanical conveyance you sit on, like a horse, you "ride" it.
if something looks more like a carriage than a horse, you "drive" it.
If something looks more like a carriage than a horse, and you are not controlling it, you "ride in" or "ride on" it (depending on whether you are inside or outside).