Why would he go to him instead of a hospital. Huhbhh

His mental state isn't right. Being together with Wooyeon only messed his view in proper relationship. InSeob thought Wooyeon will again acted crazy like he did when they're at Hawaii. As InSeob never put himseld first, he thought the best action is come to Wooyeon, tell him he will be back after the treatment, and call ambulance to come to there instead him just immediately go to the hospital.

Yup, tho now I think wooyeon would of wanted him to just go to the hospital as he’s finally changed