[REDACTED]

The other solution is good, but wanted to add one very important note:

WHATEVER MODIFIERS YOU HAVE ON CARRY OVER TO THE WATCHER RUN

All in all the run isn't too hard, but if you have the 7 minute timer on like I did, it got a bit dicey early on with a low-power weapon and two rival fights in the first biome. Once you get all the codes I'd recommend doing a modifier-free run just to make it easier.