How do robots do the underwater torch relay of the Winter Olympics? What black technology was used?

Robots are amphibious robots and underwater variable structure robots, which cooperate with each other to complete the underwater torch relay. It mainly includes three parts, that is, the robot slides into the ice and enters the water, the underwater torch transfers the fire and the robot exits the water. The main principle is to use the principle of self-supplementing oxygen before launch, and it can be burned by oxygen after launch, which not only protects the flame, but also makes the torch waterproof.