Help explain the meaning of the joke, don't you understand?

In fact, the main joke is that the two uncles are too persistent, and they all ignore life and death!

Funny point one: the distance between the two cars is only 0.000 1KM. Is it a bit exaggerated to use KM as a unit?

Funny point 2: You can think of two old people standing on bicycles swinging from side to side to grasp the balance!

Funny point 3: even if you fall, you have to stay deadlocked and continue to touch porcelain (you may not be able to fall, hehe)

The joke is a little low, hehe, everyone has different opinions. Don't spray if you are wrong. If I am right, give it to me.