Apple had added an easy way to quickly call emergency services and disable your Touch ID in case of emergency.
This new setting, which when activated, brings up an emergency menu allowing you to turn off your phone, View Medical ID and Call Emergency Services.
To activate it, simply tap the power button 5 times quickly. The feature does not automatically call emergency services (unless Auto Call is activated in Settings/Emergency SOS), but it brings up the option to do so. The feature also temporarily disables Touch ID until you enter a passcode.
The feature is in the iOS 11 Public Beta. Previously, if you wanted to temporarily disable Touch ID you’d need to shut down your phone and restart it. Not something you want to do if you are in danger and need assistance.
This new method is a far more convenient and safe way of locking out a phone, especially if you’re in a dangerous situation where someone might force you to unlock your iPhone.