Peter Gregor was one of the prisoners who assisted Junior in the attempted rape of Ellen Ripley at the junkyard. When Dillon makes it to the scene and attacks Junior, it is evident that Gregor was severely beaten as well.
Not much is known about Gregor, but he was one of the prisoners living on Florina 161. Upon the arrival of Lieutenant Ellen Ripley after a deadly ship crash took place on the planet (ending with her being the only survivor), Gregor assisted Junior in attempting to rape the woman, as she was the only woman on the planet. They were caught, and it is implied that they were beaten by Dillon after he stopped them.
Later on in the film, during the explosion, Gregor was badly burned in the fire and uses white bandaging to treat the burns. After the failed attempt to trap the Alien in the toxic waste dump, Gregor joins the rest of the inmates and uses himself as bait to lure the Alien into the lead mold. As he runs down a hall away from the Alien, he has a head on collision with Morse and the two fall to the floor. They both stand up and, assuming that the other prisoner is the Alien, attempt to attack each other before recognizing each other. Finding some humor in this situation, the two of them share a lighthearted moment, laughing and fooling around. As the two giggle at their predicament, the creature charges up from behind Morse and bites Gregor in the neck.
- In the assembly cut, Gregor's character is expanded upon and it is revealed that he is one of the few agnostic prisoners.