All the Animated Armor does is guard the door. Not past the door.

First turn:

Barbarian: advance however many feet needed to be close enough to the door while leaving the space for team, Ready "advance through the door as soon as it's opened"

Animated armor: does nothing

Cleric: advance however many feet needed to be close enough to the door while leaving the space for team, Ready "advance through the door as soon as the Barbarian went in"
Druid: advance however many feet needed to be close enough to the door while leaving the space for team, Ready "advance through the door as soon as the Barbarian goes in"
Paladin: advance however many feet needed to be close enough to the door while leaving the space for team, Ready "advance through the door as soon as the Cleric goes in"
Thief: advance however many feet needed to be close enough to the door while leaving the space for team, Ready "advance through the door as soon as the Paladin went in"
Warlock: advance to the door, open it, let their team go through, gets in the room via Dash if needed, otherwise use spell on enemies

Second turn:

Barbarian: close door with free object interraction, bonus action Rage, attack target.

Animated armor: *does nothing as the door is still guarded*


Does anyone see a hole in this reasoning?