Angular: $injector

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.5/angular.min.js"></script>
<div ng-app="hospital">
    Full Name: {{firstName + " " + lastName}}
</div>
<button id="hehe">Hahaha</button>

JavaScript

var $hospital = angular.module('hospital', []);

$hospital.controller('myCtrl', function($scope) {
    $scope.firstName = "John";
    $scope.lastName = "Doe";
});

$hospital.factory('vaccineX', function($window) {
  return {
    isInjected: function(name) {
      $window.alert("The VaccineX was injected into patient " +
          "to cure the disease X.");
    }
  };
});

$hospital.factory('vaccineY', function($window) {
  return {
    isInjected: function(name) {
      $window.alert("The VaccineY was injected into patient " +
          "to prevent the disease Y.");
    }
  };
});

$hospital.factory('patient', ['vaccineX', 'vaccineY', 
    function(biceps, buttock) {
        return {
            treat: function() {
                //biceps.isInjected();
                //buttock.isInjected();
            }
        }
    }
]);

var tmp = document.getElementById("hehe");
tmp.addEventListener('click', function() { 
	var _angular = angular;
	debugger; 
});

//window.get

//debugger;
//var $nurse = angular.injector(['hospital', 'ng']);

//var Treatment = function(patient) {
//	debugger;
//    patient.treat();
//}

//$nurse.invoke(Treatment);