Some experiments were originally from the outside. Being caught, not only are they missing to the outside world, but their loved ones probably won't be able to recognize them. They each handle it differently.
Goop can't really remember anything from before his experimentation. He hates thinking about it, too, as the vague memories cause him to break down.
Suicide apparently had such a horrible life outside that he practically embraces his new life.
Richie misses his mother, especially since he never told her where he was going. He's also extremely worried as to whether or not she'll be able to know it's him, assuming he ever gets back out.