I'd suggest a posable figure (with bends off on the joints). Even though a morphing prop is possible, the posable figure is more versatile - for example, you could hide/show the elevator or door body parts as needed.
It might even be useful to designate the four walls and the ceiling as separate body parts - removable (hidable) walls are a great benefit for interior scenes.
That actually mirrors interior sets used in the television/film industry - retractable/removable wals for easy camera access.

The pen is mightier than the sword. But if you literally want to have some impact, use a typewriter

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