Adjusting speed of play and hiding _hit zones

this is a two part question placed in the same thread because im certain theyre fairly simple to you experts:
? #1
can i adjust the speed of play of a timeline. For instance when a button is clicked i want the timeline to speed up to a certain point and stop. Not to play at the normal speed?

?#2
i have the following code


mousex = _root._xmouse;

//define mousex as the x coordinate of the mouse
if (mousex >= hit_right._x){
pic_mc.nextFrame();
//if the mouse is on or to the right of hit right, move movie to the right
}

if (mousex <= hit_left._x ) {
pic_mc.prevFrame();

this works fine, however if i load a movie clip on top of this one the _hits are still active…when the loaded movie clip is unloaded, the movie behind has moved based on cursor movement. how do i deactvate the _hits on command?