How long 120mg. well, the half-life of methadone can be up to 59-hours, so after 2 and half days you would still have 60mg's in your system. But this doesn't take into account multiple doses.
A third type of lock is a security lock. This lock is like a typical password, to prevent someone other than the owner from using the phone. If activated accidentally, the user manual or carrier customer service can usually tell you the default code.
Require Passcode: By default with this setting, as soon as you lock your screen, you need to enter your passcode to unlock. If you don't want an immediate passcode requirement, change this setting. (For your security, if you use Touch ID or Apple Pay, you can't change the immediate passcode requirement). Allow Access When Locked: Use this option to allow access to some features when your device is locked, including Today View, Notifications View, Siri, Reply with Message, Home Control, and Wallet.