Vault Wardens must hate you to seal doors (9196)

A warden must be nearby and have you as a foe to seal doors.
Otherwise, it's possible for a wandering summon or undead pal to
aggrevate the warden and then whack you from across the map. The
door-sealing mechanics are tied to you being the target, so it
doesn't make that much sense to allow wardens to target your summons
without rewriting that code.