"I don't think any companion of the Doctor's is bad at it," Jack winked. Hence why they were all picked. Or drawn to each other in impossible situations that could lead to no other outcome than travelling together.
"Oh, the spire. I was warned about it. Apparently it's a dangerous, tricksy little thing." Which naturally meant it was perfect for them. "Oh no, that is a marvelous idea, Miss Amy Pond. We shall cause trouble for everyone." Or, maybe something good would happen. Jack was on board with good. This wasn't the train, but they were still stuck here, and he'd like a familiar face or two about.