What would happen if a survivor gets hooked for his/her very first time and doesn't handle the pain and passes out on the hook.What would the entity do?
Consider the perk “Knock Out”. Supposedly the hit is so hard that the survivor cannot cry out, and is essentially unconscious. The end result is that other survivors can’t find them (no red aura).
I would say that a survivor passing out on the hook is the same result: aka blindness to other survivors.
That said, from the lore perspective, I would say the entity gets an easy meal. Since they can’t find him, nobody rescues the survivor during the first stage. Furthermore the unconscious survivor is not awake to struggle for the second stage.
My assumption is that the Entity grants survivors higher pain tolerances and some sort of increased durability (which would explain the amount of beatings and chainsaws they can handle) so that they can stay awake on the hook, and also why they don't die from their injuries.