We apologize for this issue, dying immediately during the blackout was believed to have been fixed months ago; this was obviously not the case.
The game has been updated and the issue should finally be resolved now, along with several other improvements. We completed it multiple times to verify such, but He has fooled us before.
Hiding will only stop Him from killing you if you hear His footsteps approaching. As per His rules, if you hide in response to any other behaviour He will simply come in and kill you.