Today I thought I'd discuss a little about how you'll stumble across the creatures of Fallout Who 'post-quest'. As you're unlikely to stumble across a Cyberman or Silurian before encountering them in their respective and unique quest, we needed to establish a balance to the gameplay of New Vegas that wouldn't thoroughly impact it for you.
In other words; we didn't want to fill the Wasteland with armies of lethal Daleks.
So to counter this, we came up with a clever strategy that would allow your encounters with the aliens of the Universe to be woven into the game in an unintrusive fashion.
Post-Quest encounters vary. I shan't explain in what capacity you can expect to stumble across an Auton Duplicate, or be advanced upon by a Weeping Angel as they'll ruin the story for you, but I will try and emphasise, that it's clever. It's very, very clever.