Responses
Correct me if I'm wrong pls but I think it was bound to happen as that's the trap ido set for haeshin to crumble in the current timeline. So no matter what sejin will still get that slap but just not from ido this time.
Now remembering back when sejin came back home with the slap haeshin's POS president did, the memories must have came to ido of how he too used to think that way of sejin and spoke the same words like that POS. Oooooof the angst rereading back the happy moments for this past moment