Angular2 routing breaks when navigating in a method call within the subscribe callback of an observable

after.ts

private submitLoginForm() {
		const data = this.formGroup.value;
		this.lastSubmission = JSON.stringify(data);
		const toast = this.toaster.toast({
			title: "Logging in..."
		});

		this.tellwell.doLogin(data)
			.subscribe(result => {
				this.toaster.clear(-1, toast);
				if (!result.success)
					this.handleUnsuccessfulLogin(result.message);
				else {
					this.lastSubmission = "";
					this.unsubscribeAll();
					// this.doAfterLoggedIn();



                    this.router.navigate(["/"]); // this works
				}
			});
	}

before.ts

private submitLoginForm() {
		const data = this.formGroup.value;
		this.lastSubmission = JSON.stringify(data);
		const toast = this.toaster.toast({
			title: "Logging in..."
		});

		this.service.doLogin(data)
			.subscribe(result => {
				this.toaster.clear(-1, toast);
				if (!result.success)
					this.handleUnsuccessfulLogin(result.message);
				else {
					this.lastSubmission = "";
					this.unsubscribeAll();
					this.doAfterLoggedIn(); 
				}
			});
	}

private doAfterLoggedIn() {
		let returnRoute = this.route.snapshot.queryParams["ReturnUrl"] || "/";
		this.toaster.toast({
			title: `Welcome back!`,
			duration: 2000
		});
		this.router.navigate([returnRoute]); // the call that was failing/breaking the router
	}