I'm a quality engineer doing testing and automation for InterSystems cloud offerings.
Outside of InterSystems, I teach in the graduate software engineering program at Brandeis University.
Your Windows user and your IRIS user may be (and often are) different. You need to authenticate to IRIS as well, which is why you need uid and pwd.
Robert Cemper has a good idea for getting the container running so you can do work. Or you can use iris-main to tell IRIS not to start when you bring the container up.
The user and password for EmergencyId is one you define for that session, so it can be whatever you choose. See https://docs.intersystems.com/iris20241/csp/docbook/DocBook.UI.Page.cls?... for the details.
Knowing more about why you want emergency mode can help us get you a better answer.
Cold backup is one of the options documented in the Data Integrity Guide.
But a lot depends on what you mean by "all data" -- don't forget installation files, license key, journals, any stream files you may have, and on Windows remember that installation puts some keys in the Registry. How much of this you'll need to restore depends on the kind of trouble you encounter. For example, if you want to restore a database, but the instance is otherwise healthy, the Registry is likely in working order, but if the entire server is destroyed, you have a more complicated recovery.
If you need to be able to bring the instance back to its latest state (roll-forward recovery), you'll need journal files that won't exist at the time you take the backup so you may want to backup journal files separately during the working hours.
It would be a good idea to protect your installation .EXE file as well, so that you can install a fresh copy of the exact version you use. Down the road, that version might no longer be available from the WRC.
Take care to preserve the correct ownership and permissions on files so they are correct when they are restored from NAS.
Your account team can be a good resource.