Spectacular play by Ryze from LoL. How did he defeat the enemy and make it out alive?

One of the players shared a clip of a successful top lane action. What happened?
The fights in League of Legends, especially the 1v1 ones, require the player not only to know the champion but also to be inventive, have good reflexes, often using vision (e.g. by entering bushes) or even using the technique of diving under the tower.
Some players like to take risks and are drawn to fight the enemy from the very first minutes of the game. Unfortunately, risky actions do not always end 100% as planned. The point is not even that during an attack, you will accidentally die from the enemy’s skills, but also that you lose your own life after a successful kill. It’s always best to get the kill and get out alive.
The hero of today’s video really wanted to beat his opponent in the top lane. He also devised a clever plan to get away from all the fight with a bit of health left. How did he beat the enemy under his tower?
Ryze versus Teemo
A player with the nickname Lv35_Chungus posted a short video of the action on Summoner’s Rift’s top lane. It all starts innocently enough. Lonely Ryze tries to destroy his opponent’s tower. After a while, Teemo returns to the line with full health. The player attacks him and notices that he has a chance to kill him under the turret. He tries to stay focused for a while, and eventually decides to take the final steps – he uses R under his feet, kills the enemy, and runs away to his side of the map.
You can see in the video that Ryze came out of this with really little HP. He would have died if the tower hit him one more time. He knew this, as well as the fact that he could dodge its hit with his ultimate if he played it at the right moment.
Some people believed that it was probably an accident and the author of the film was simply very lucky. But it was not so. It turns out that the action was carefully planned a few days earlier when the player started practicing it on the Training Tool.
The author of the video wrote:
Yeah I practiced it in practice tool 3 days before pulling it off in a real game. I messed it up a couple of times prior to this because I was so overly excited whenever I got the chance to try it. The timing could have been a bit earlier in this one

One of the commenters wrote:
Was expecting you to land on top of a teemo shroom and die after that insane play, but this is pretty good too.