I have a problem almost exactly similar to How to open a door that has the insides of a door handle inside without a door knob but I have a more complicated mechanism.
Basically while installing the lock and checking for alignment, I inadvertently shut (I won't say "locked" because the mechanism isn't locked) myself out of a room. Inside the room is the rest of the hardware and most of my tools.
How can I unlock this from the outside, without the doorknob?
Also, since this is a keyed entry system, how can I visually confirm whether it is locked or unlocked, and how would I unlock it from this situation?
Depicted below is someone else's photo of the exact lock/latch mechanism I'm dealing with.