Leith nodded. "We started with just one, considering that we initially thought that'd be enough to save our area. We decided to preserve the other four, so that we could take them elsewhere to work their scientific magic." He tapped his fingers against his knees, but then stopped when he picked up the story again. "We had seven scientists left; the vault had many bright minds in there, I suppose for this purpose. I wasn't one of them, mind you. At that point, all that I cared about was Christina. Anyhow, we weren't prepared, to say the least. It'd only been a decade since the bombs fell, after all, so if you think radiation is bad today...you've got no idea, sweetheart. Half-life works wonders, when given the time to do it."