I need help on a mission in Fallout 3.?

I'm doing the side mission in Fallout 3 called "Rescue From Paradise" and I fixed the junction box and I also have the box key, I pickpocketed it from Eulogy. Squirel and the other kid leave but Penny won't leave without me freeing Rory from the box. when I do he tries to follow me out but every time I get close to the exit the slavers kill him. p.s. this also happens when I try to set free the people I enslaved earlier in the game i.e. Susan Lancaster, Arkansas, Red, and Flak. Any idea how to avoid this.