August 3, 2025 4:37 PM (GMT+2) At this point I’m considering merging all the “how to open safe…” into a single mystery.

August 16, 2025 6:12 PM (GMT+2) I actually did effectively merge all of it into The 8 red letters.

In any case, thanks to a hint from a friend which allowed me to relate “gates” and “gaits” (which in fact is a hint provided in A New Clue), I was able to figure out the code for this safe. You need to count all the “small gaits” throughout the paintings in the room, separating the count into the two types of painting that contain small gaits (woman and man). One of the numbers is the month, and the other is the day. It’s also not ambiguous because one number is 4 and the other 15. As such, the code is 0415.