John had indeed looked, once he'd worked out what was going on. He straightened up, looking back over to Sherlock with a perplexed, thoughtful expression.

"Sherlock... I think- I think you might want to take a look at this. I think they've been doing these Games for a lot longer than I thought, and- it's possible they used this Arena before, too."

He didn't mention the sick feeling of revulsion at having just watched a child cut down. It was obvious- and, as Sherlock was keen on reminding him, caring didn't solve cases.