We wouldn't ever recommend trying to transplant specific tables between databases. An import is the recommended approach as to import users, there are several other steps that have to be run first. You would then deselect all other steps though.
You will need to create "empty" data/ and internal_data/ directories to read from. I use this in quotes as they need to look like a real install -- we do this intentionally to ensure people enter correct paths. It may be easiest to point at a copy of the directories from another install (though they shouldn't actually be used if you're just importing users).