Disclaimer: Not mine. Goes with s1 Nocturne.
He didn't know the exact number of tapes, wasn't sure he wanted to. But he did know that someone had to watch them, and he knew he didn't want them to.
Because even if it was crucial to their case, even having seasoned detectives under his command, he didn't want this in their heads. What they saw day in, day out was more than enough. He didn't want to add the burden of the contents of those tapes. It was akin to asking one of his detectives to eat thier gun. But despite all that, one of them had to sacrifice their sanity and watch those tapes.
He didn't ask them outright, couldn't really. Simply suggesting that one of them has to was more then his shoulders could carry. He certainly couldn't assign anyone. If suggesting was too much, ordering would break him. To tell someone to watch those tapes could be classified under torture.
But someone had to.
So he suggested it.. 50, 100 more kids on those tapes.
He knew Elliot wouldn't, couldn't in a million years watch something like that.
He knew the same was true of Olivia. She felt everything too deeply.
He knew that Monique, too, was out of the question. She may have been tough, but she felt it, too, even if she tried not to.
John was the only one left. And sure enough, in the heartbreaking silence following his statement, John said, "I'll do it."
He wanted to stop John from watching it, but there was always something in the detective that took the greater suffering upon himself. John was aware that his younger colleagues couldn't watch those tapes and, if he allowed himself to be honest, he really couldn't stomach it either.
But someone had to.