Emergency calls from iphone

Is your Auto Call turned Off. If yes, nothing of this will happen unless you use the slider first.

Here's how it works

When you make a call with SOS, your iPhone automatically calls the local emergency number. In some countries and regions, you might need to choose the service that you need. For example, in China mainland you can choose police, fire, or ambulance. 

You can also add emergency contacts. After an emergency call ends, your iPhone alerts your emergency contacts with a text message, unless you choose to cancel. Your iPhone sends them your current location, and, for a period of time after you enter SOS mode, it sends updates to your emergency contacts when your location changes. 

Here's how to make the call on iPhone 7 or earlier: 

1. Rapidly press the side (or top) button five times. The Emergency SOS slider will appear. (In India, you only need to press the button three times, then your iPhone automatically calls emergency services.) 
2. Drag the Emergency SOS slider to call emergency services.

Use Emergency SOS on your iPhone - Apple Support

https://support.apple.com/en-us/HT208076

Both will be contacted, but it will contact emergency services first, then your contact(s). If you cancel the call before it is initiated, no one gets contacted.