Diomedes took rest to watch the waterfront of the beach. Another successful raid of a Trojan stronghold had taken place the day before, and for now there was calm. Of course before he spotted something sneaking it’s way out of the Camps; he took the moment to grab his sword before following along, knowing better than to call out.
He was out of his armor, just with his sword and a hope that this wouldn't be too bad of a situation. Not that he couldn't hold his own but just that he didn't really want to deal with anything at the moment.
Diomedes was tired; he hoped it was just one of Agamemnon's herald's leaving back to the main camp and not some like, spy exiting the camp to go snitch on all of them to Hector and the rest of the Trojans. But it was always an option; but at the very least it meant Diomedes would be doing everyone a favor by catching a spy.