It's pretty easy - you're asleep, phone sound/vibration wakes you up, you're on call so you pick up the phone, it face unlocks, through your unfocused eyes you

It's pretty easy - you're asleep, phone sound/vibration wakes you up, you're on call so you pick up the phone, it face unlocks, through your unfocused eyes you see a thumbprint icon and aren't sure if face unlocked worked in the dark, so you touch it. A second later you're wide awake and wondering what the hell was that mfa for...