I wonder if Behavior are ever gonna expand on that.
Talbot thought he was writing down his research, the Entity made him write down "Death is only the beginning". He doesn't know what it means.
It's likely a callback to 'death is not an escape,' since the Entity just brings you back when you die.
because his death in the real world marked the start of his new life in the entity's realm
Makes sense, I like this answer the most out of the three posted so far.
The Mummy DLC confirmed
A couple of ideas.
It appears you can die repeatedly in the entity's realm, so possibly a warning that you WILL die and that doesn't end your torment.
It could also represent that if you keep dying and eventually lose all hope you become a new killer for the entity. Kind of like how hollowing works in dark souls.
You don't become a killer when you lose all hope/emotion. The Entity get rid of you and throw you in the garbage bin AKA the void.
You are correct. According to the lote that's what happens.
Yet, Vigo left the void and it is suggested that putrid serum allows you to leave.
It is an underdeveloped area,as that is all of the info supplied about the void as short paragraph.
Other than that little is known so my theory still has a chance to be true or at least retconned in.