"It's not so surprising. Rocks high in silicates that melt due to extreme temperatures and cool rapidly form into glass, much like these," he explained, his hand motioning towards that spike. It was interesting to see, but the ideas he had of what may have caused it made him uneasy. All he could do was hope it had been the humans who'd done it to themselves, and not of extraterestrial origin, which would mean the threat could still be out there.

But he was letting his thoughts get away from him.

Again, his attention turned back to focus on Gabriel. "Taken in?" he asked, clearly confused, but after a few moments of thought, his expression turned to a mix of concern and annoyance. Gabriel had seen it, this world, before the disaster. The Doctor doubted it had been through time travel. "Memory manipulation?"