Migrating legacy PHP to Symfony stalls on shared resources. The database, the session, the mailer all exist twice, and duplicating that code is the cheap answer nobody wants to maintain. Calling into Symfony from outside the framework looks impossible, but it isn't. This talk shows how to boot the container from legacy code and get full dependency injection on both sides of the migration, with the trade-offs and the sharp edges spelled out. Assumes familiarity with Symfony's DI configuration.