indeed, i won't say i haven't used prefabs, but i've never released a map that uses them, they can be useful for learning from, much like decompiling.. both having undesirable flaws and errors.
so just look at what makes up teh prefab, and try and make your own version. Also, check teh Not-Solid flag, or set up a func_train style scenario, in which you could make it totally illusionary.
plus you could make a random searchlight pattern, rather than just back and forth