She'll almost certainly be asked a weird question. Mine was "why can you have a pun in English but not in mathematics?". The important thing is to be game. I responded with the joke "proof" that 2*2 = 5, but made a mess of it, because of nerves, I forgot the proof halfway. That probably lost me a brownie point, but overall it didn't matter, they still let me in. She'll also be asked some mainstream questions, like "Which author do you think has influenced your ideas the most?" She might say "CS Lewis". They'll say, "How has he influenced you?", which is quite difficult, because she's probably grasped the first name she can think of. So she might stammer out the he's made he think more seriously about Christianity. Now they'll move in for the kill. The important thing to remember is that everyone gets themsleves into that position - the harder the interview seems, probably the better you're doing. They'll say, "surely Lewis was just recycling ideas from GK Chesterton, in a rather crude way." What they're doing is putting up some perfectly conventional arguments. They don't necessarily think that themselves. Now if she hasn't read Chesterton, then say so, that's OK and they'll just try another line of attack. Suppose she has. The thing to do is to first acknowledge the strength of the argument, "Yes, I was surprised when I read GK Chesterton myself to find that Lewis uses many of the same arguments, and in the same style." Then say why you still think your position is right, "But Lewis influenced me more, because, having been an atheist once, he's got a deep understanding of how atheists think - for example he says how he thought it a fine thing to say 'Yeohshua" instead of "Jesus". Chesterton doesn't have that. I think Lewis added something really new."