Did you try the "Fire Wall?" Mine is located in the path "entitybank\generic\Benge sprites\emission"
Put a 3 x 5 ground platform down on your map. Select the "fire wall" place it at the top of the map. Put your player marker down at the bottom. Click the test button. It works for me. I am using FPSC v113 beta 1.
Addendum:
A tip for using sprites; especially if you are using a surface sprite that takes up a full block and you want to cover a larger area. Select the sprite you want and then before putting it down, press the <B> key twice. This will lock it into a single square. Then you can just place the sprite down one right after another and they will be aligned perfectly -- close enough it is hard to notice. This is also useful for segments.
The past has a lot of memories to hold onto; but, today is chock full of new adventures, and, the future shouts out, "The best is yet to come!" -- TerryC