He said patience because it's difficult to beat Rose in the poker game. For current update there is a another way to get that code. You have to complete Faith's quest successfully. After that her ghost will appear in Class 3-2 of Evergreen University. Splash is with cum water or dagger then wait until it's wandering again and talk with her until she tell you the code. To know more about Faith's quest, read Wendy's vessel section in 'All Animations and Spoilers' thread.