Scratch

I am doing a project for school, and I have a problem. I have lasers that appear and vanish every few seconds, and the player must navigate them. I am using a simple system of:
       -Forever
       | SHOW
       |WAIT 1 SEC
       | HIDE
       | WAIT 2 SEC
       ____________

To control when the lasers pop up.

This works fine, but then, once the player makes contact with an object called SER (Smooth Endoplasmic Reticulum) , SER broadcasts "Card Show." Card show causes a card to pop up on the screen which displays information on SER. I have the scripts set so that when key "F" is pressed, the SER card will hide.

Now I want the lasers to hide, and I have it set so that when "F" is pressed, not only will the card hide, but the lasers will too. What is happening is that the forever loop shown above causes the order to hide issued from the "F" key to happen, but then it just goes right back to the hiding and showing of the lasers!

I was wondering if any of you guys know how to stop the script in the forever loop (but not ALL the scripts) when f is pressed so that there won't be random lasers popping up every few seconds throughout the rest of my game

If you need any more clarification on the problem, just ask me in a post.

Thanks so much- FCbarcal0na