When I was young, sometimes my heart would randomly seem to stop for a bit, then beat really hard and slow, then gradually speed up to normal pace.
I have no idea what it was about but it's stopped now, it hasn't happened for around 10 years.
If you jump on a moving bus you're effectively jumping diagonally, that's your jump + the movement of the bus. generally, air resistance slows you downut inside a bus the air is being moved too, by the walls of the bus so I don't think you'd even move any. Maybe on an open top bus.