Knowing full well it would mean by the time he was left go they probably wouldn't have found anything at the site and it would frustrate the process. Twenty four hours is a short time given the search could take days. Also it's dark more or less from 7:30 pm to 7:30 am which further curtails the search efforts.He waived his right to sleep overnight so he must be a tough cookie.
There was a newspaper reporter on with Matt Cooper earlier and you got the impression he was about to blurt something out but seemed to stop himself mid sentence.