I notice you've asked for a paper titled That phrase does not correspond to a known academic paper, technical standard, or widely recognized code system. It could refer to:

: Walk to the safe and use the "Push" and "Pull" commands on the handle in the exact order you saw the shopkeeper use them.

There isn't a traditional numerical safe code here. Instead, you must collect Soul Shards (purple crystals) to unlock the Ring Altar at the end of the level.

: Ask him about the Swordmaster . While he is gone to check on her location, you will have a window of time to act.

Here’s a quick guide: