The hospital scene was after J saved him from a dungeon and then J had to go inside the dungeon he's been stuck in, while J was in the dungeon Sayoung was experimented on and then "saved" (we don't really know what really happened yet).
Yeah. So after Euijae or J left to go to the West Side Rift, Sayoung was kidnapped from the hospital and was experimented on again that is when Jung Bin saved him.
Sa-young got saved by J when he and his family's house got swallowed by a poison rift. He did not get experimented then and was just living a normal life with his family.
Then J went into the rift and a few months later, he gets kidnapped and got experimented on for a whole year.
Then here is what happened after he awakened. No, he didn't awaken because of the experiments (though, that was the goal of the experimentations).
Was Sayoung experimented twice?
Didn't J save him and bring him to hospital? Was he kidnapped again?