Ooh, great catch! That looks to me like it has a normal door handle, the keyhole, and additionally a manual knob for locking it lock from the inside.

I think the question remaining question is unanswerable unless we've all forgotten about a scene: is the outside handle functional (in which case it can be opened without a key, so long as it hasn't been manually locked from the inside) or not, like mine (in which case it can't)?