“If one strikes a man so that he dies, the one who killed must also be killed.” - Literally “killed, he must be killed.”
This is a hint to Cain who killed Abel - for when Abel was later reincarnated as Moses, he was called “a man,” as in “...this man Moses...” First time Cain was reincarnated as an Egyptian, whom Moses killed, and the second time Cain was reincarnated as Korah, and again Moses killed him.
“But if he did not lie in wait, only God caused this to happen through him, then you will separate for yourself a place of refuge.”
God told Moses to separate three cities of refuge - literally for Moses himself. Angel Samael was acting as an avenger of blood for the Egyptian. The angel's claim was that Moses did it intentionally, and therefore he should be killed. But in truth Moses' purpose was to help the Egyptian's soul and to correct it, and that is why Moses killed him by pronouncing the explicit name of God, which made his killing unintentional. This is why “he did not lie in wait” - talking about Moses, but “God caused this to happen” - still talking about Moses, and thus “you will separate for yourself a place of refuge to run there (שמה) ” for Moses (משה).
Art: Frederick Arthur Bridgman - By the City Gate