One variation on the question: When Debbie and I are diving on our own, we use a large innertube like float for our dive flag, and it has a center area in which we put a water bottle, a rescue breath barrier, and a few other first aid supplies that may be useful in the water. Our big DAN kit stay ashore with the O2 kit. That practice notwithstanding, the priority with a distress diver is to a) surface them safely and b) get them to shore or the boat. Time is everything.
DivemasterDennis
DivemasterDennis