He moves to the wall, thinks of the space on the other side of the wall, above where his own head would be, and he manifests his owl familiar, Shanks.
He tells Shanks telepathically, Give ‘em hell, Shanks!
He urges Shanks to pester those right next to the door, and then to head to the main spell caster.
He then uses his bonus action to cause the mage hand to open the door quickly!
Action: cause Shanks to appear from his pocket dimension to the other side of the wall, and tells Shanks to pester the guys by the door first, and then the caster.
Bonus Action: use mage hand to open the door.