Delete a firebase item from ionic 3

I get an error in removing a firebase item. I can add but not delete if I delete, I delete the entire table.

My code:

    import { AngularFireDatabase } from 'angularfire2/database';

    export class LoginPage {
      arrData = [];
      $key?:string;
      myInputName: string;
      myInputNumber: number;
      usuarios:any = [];


      constructor(public navCtrl: NavController, 
                    public navParams: NavParams,
                    private afDB: AngularFireDatabase,
              private action: ActionSheetController) {

     this.afDB.list("myUsers").valueChanges().subscribe(_data =>{
            this.arrData = _data;

            console.log(this.arrData);
        });
      }
btnAction(usuarios){
  console.log(usuarios);
  this.action.create({
    title: '${usuarios.myInputName}',
    buttons: [
    {text: "Editar",
    handler: ()=>{
      //tenemos que pasar un parametro para editar.

    }
  },
    {text: "Borrar",
    role: "destructive",
    handler: ()=>{
      //tenemos que pasar un parametro de eliminacion.
      //this.afDB.list("myUsers").remove(usuarios.$key);
      console.log(this.arrData[usuarios]);
      //this.afDB.list("/myUsers/").remove(this.arrData[usuarios].$key);
      this.afDB.list('/myUsers/${ this.arrData[usuarios]}').remove();

    }
  },
    {text: "Cancelar",
    role: "Cancel",
    handler: ()=>{
      console.log("El usuario a cancelado la opcion");
    }
  },
 ]
 }).present();
}

}

  <ion-list>
    <ion-item *ngFor="let item of arrData; let i = index" (click)="btnAction(i)" > 
      <h3><strong>Name: </strong>{{item.myInputName}}</h3>
      <h4><strong>Age: </strong>{{item.myInputNumber}}</h4>
    </ion-item> 
  </ion-list>

I've tried all this.afDB .... but it's not going. Thanks in advance