This app was mentioned in 4 comments, with an average of 8.00 upvotes
I'm not aware of any kind of Android equivalence to this (though the lock screen does let you make emergency calls directly without unlocking the phone).
There are, however, apps that can do things like track you by GPS and alert chosen contacts if you don't check in. There's fake phone call ones that can be used to get out of things like bad dates. Ones to immediately send mass SOS messages out. bsafe and ReactMobile are two examples.
For android (it might also be available on IPhone) there's an app called bSafe. Here's the link to the android version. It has a ton of features and will share your GPS location if your emergency contact network is notified.