Multiple FLVs loaded properly

Question

Ok,
On my main timeline i have some buttons. When you click a button you are diverted to the a frame label on the main timeline.
When the timeline stops at say frame 2 an flv is loaded into an empty movie clip on the main stage.  If you click on button 2, same thing. So in total I have about four FLV's that play when a button is pushed. If i keep clicking my buttons to test the smoothness of my flv's, after about three clicks from navigating between my frames/loaded flvs, my entire main movie becomes slower.
Each FLV is about 5mb.
Below is the code that gets initated when I click my button and am taken to that frame. My question is this, if i'm jumping between FLV's at every button click is the FLV that played first still playing and causing the entire main movie to slow down? Is there a better way to manage this? Do I have to unload the movie being played when i click? I'm trying to see if there an more efficient way to have smooth streaming from my flv. The flv that is getting initated is simply looping when it's done and servers a 'moving background'.
is there something else i can implement into my code that will keep my loaded flv's playing smoothly? Thanks,
this is the code on the main timeline that loads my external swf that will load the FLV
var myLoader:Loader = new Loader();
addChild(myLoader);
var url:URLRequest = new URLRequest("theexternal.swf");
myLoader.load(url);
This is the code that resides in the external SWF that will initiate the FLV.
import fl.video.*;
function onFLVComplete(event:VideoEvent):void {
      event.target.play();
swl.addEventListener(VideoEvent.COMPLETE, onFLVComplete);

Answer 1

ok,
so you are saying that the "unloadAndStop() is a Loader method" should be placed on the main timeline where my button is pointed to instead of inside the button?
example.
my button that points to frame 2 of the main timeline will also load the flv. Frame 2 in my main timeline simply has a stop(); action
How does the code look if i want to unload the physical movie that i created called 'night_mov'