what are the grounds for telling the difference, so i know how to approach re-establishing communication? thank you in advance.
I think at death’s door he/she doesn’t want to see or talk to you at all
Yes, what @Kaila said. Death’s Door seems to me to be the moment when your ex is actively trying to remove you from his/her life. i.e blocking you.
Drift is a stage where you might be broken up, but you’re still in contact, or he/she is open to contacting you.