John was upbeat, friendly, and loved movies, but he especially loved Demi Moore, who was the film's star. When she was shooting a scene, John was there, watching. Always. Two particular things about this stick in my memory.
The first is that later in the production when John finally had his particularly-big scene, everyone was surprised to see Demi there on the soundstage, as well, even though she wasn't in the sequence. It was odd to see since, when actors aren't filming, they're almost always back in their dressing room, resting or working. But Demi was there on set. And when John saw her, he was thrilled, absolutely overjoyed. I remember her explaining to him, "Well, you're always on the set watching me when I'm filming, so it was only fair that I come and watch you." And it wasn't a token appearance for the first shot, which still would have been thoughtful, but she stayed the whole time, probably 45-minutes to an hour.
The other thing I remember related to all this is that on John's last day of filming, Demi bought him a gift. A puppy. As you might imagine, he was thrilled by that, too.
I was able to track down most of that scene. The video quality is a bit soft, but it's fine. In the film, John played a a young man in prison for having killed his parents because he insists God had told him to. (The movie was about prophecies and the end of the world, and this is all tied into that. My recollection is that the parents were pretty high on the Sinners Scale. I'm not saying that that justified them being killed, or even that the son did hear voices, just that that's part of the plot, as well.) In this scene, Michael Biehn played Demi Moore's husband, a lawyer trying to represent the young man who doesn't really want to be represented. Akosua Busia is another lawyer brought in to help.