Dynamic Observable Merge 2

Merge Observable dynamically to a source

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/5.0.1/Rx.min.js"></script>
<div id="result">

</div>

JavaScript

var resultdiv=document.getElementById('result');
function print(message){
	var paraEl = document.createElement('p');
  paraEl.innerHTML = message;
	resultdiv.appendChild(paraEl);
}
var startTime = new Date();

var fixedObservable = new Rx.Subject();
var subscription;
function subscribe(){
	subscription=fixedObservable.subscribe(function(value){
		print('subscriber 1:'+value+' :after '+(new Date()-startTime)/1000+' secs');
	});
}
function unsubscribe(){
	subscription.unsubscribe();
}
// Subscribe to the fixedObservable(i.e Subject) initiallly
subscribe()

//Unsubscribe and resubscribe after 11 sec here to see what
// happens in that period.
//Observation: The values generated in that period are not received as needed.
setTimeout(unsubscribe,11000);
setTimeout(subscribe,22000);

//just a simple check with multiple subscribers later.All the
//subscribers get the latest value. 
/*setTimeout(function(){
  fixedObservable.subscribe(function(value){
   	print('subscriber 2:'+value+' :after '+(new Date()-startTime)/1000+' secs');
   });
},30000);*/
//setTimeout(function(){},)

//Initial Observables which feed the data to fixedObservable
var dynamicObservable1= Rx.Observable.interval(4000);
var dynamicObservable2 = Rx.Observable.interval(5000);
var counter1 = 0;
//subscribe to dynamic observable and pass the data to fixedObservable
dynamicObservable1.subscribe(function(value){
  counter1 += 1;
	fixedObservable.next(counter1 +'th value from 1');
});
var counter2 = 0;
dynamicObservable2.subscribe(function(value){
	counter2 += 1;
	fixedObservable.next(counter2 +'th value from 2');
});

//create a dynamicObservable after 5secs to feed the data and 
// then destroy it after 2.5 sec i.e at 7.5 sec from start.
//Observation: Value from this stream stops
setTimeout(function(){
	var counter3=0;
	var dynamicObservable3 = Rx.Observable.interval(1000);
  var subs = dynamicObservable3.subscribe(function(value){
  	counter3 += 1;
		fixedObservable.next(counter3 +'th value from...