remove launchMode="singleInstance" to get panic response working
Created by: eighthave
If an Activity is set to singleInstance, then it immediately sends a cancel to the Activity that called with startActivityForResult(), therefore this Activity cannot get the sender of the Intent. getCallingActivity() returns null.
"[I]f the activity you are launching uses the singleTask launch mode, it will not run in your task and thus you will immediately receive a cancel result." https://developer.android.com/reference/android/app/Activity.html#startActivityForResult%28android.content.Intent,%20int,%20android.os.Bundle%29