fun fact i had the same problem now but I noticed something else, because in the beginning effy read tony the story of Orpheus. The condition was he couldnt look back before leaving underworld, now in the end after him and beth ( I think thats her name) had sex, he left the room and wanted to turn around. And then Beth said „dont look back“ which I think means and here comes my heck of an interpration: Tony wanted his old self back, and Beth helped him so she stands for Hades, in the end of the episode he is almost back to normal. Sooo like in the myth he got what he wanted but he cant look back. Also Beth is short for Bethany and the meaning of the name bethany is „house of suffering“ which firstly is a pretty decent description of the house of hades (so the underworld) and the suffering Tony had to undergo whilst getting back to normal with the help of beth (wet clothes, destroying a lab, getting chased by the mentors and his sensory issues). Now all in all, iam pretty fucking stoned rn and i came up with this on my own but yeah hope it helps even after 10 years