[ spoilers. he can hear river song laughing, somewhere. wherever/whenever it is she is. ]

Much as I would love to tell you about all the great and not-so-great things to come, not telling people about those things is one of the number one rules of being a person from the future living in the past. Time may be fluid and always fluctuating, but some things need to happen. And you don't want to be the one that does something to stop them from happening.