Handle error in ionic Select

I have an ionic select with a list of users,
In this list i have an option that will redirect me to another page:
My problem is my select is waiting for the _id of the user, i want it to act differently with my last option ( the redirect )

Is there a way to handle this please ?

      <ion-select interface="popover" [ngModel]="selecteduser._id" (ngModelChange)="selectUser($event)" (ionChange)="onChange($event)">
        <ion-option *ngFor="let user of users" [value]="user._id">
          </ion-content>{{ getUserNickname(user }} </ion-option>
        <ion-option>Go To Modal</ion-option>

So i want when i click on my Go To Modal, it will redirect me to my modal.
My problem is that it will thrrow an error about user._id, is there a way to avoid this with a handler please ?

There is my ts

      onChange(value: any) {
        if (value === 'Go To Modal') {
      openConfig() {
      selectUser(userId: string) {
        this.selectedUser = this.users.find(b => b._id === userId)
        event.preventDefault(); // ?????