Batman opened the door without knocking, what surprised him. He had just crawled into bed, trying to make the best of the remaining 7 hours before Clark Kent's holiday ended and "his flight" landed in Metropolis.
"Oh - hey! Did I forget something at the debriefing?"
Batman silently closed the door behind him.
"Is something wrong?"
Superman tried to get a fix on his teammate's face, but the man in the black uniform seemed to do his best to avoid just that. Instead he kept still a couple of steps from the closed door, looking neutrally at the half naked hero in bed. Or was that completely naked? Batman estimated that Superman hadn't brought Clark Kent's suitcase to the HQ, why he would only have his uniform to wear. And since he wasn't wearing that at the moment…
"This is the rules:" Batman started in a strange voice. It was not the usual growl of Batman, but not quite Bruce Wayne's lighter tone either.
"1." He illustrated the figure with a raised index finger. "If you start talking or ask questions after I lock this door, I will leave at once and pretend this never happened. All surveillance is disabled, locked in a loop, leaving you with no evidence of any kind."
He had Superman's full attention. The Kryptonian didn't quite dare hope anything yet, but Batman saw his back straighten and his look sharpen. The caped crusader took it as a good sign.
"2. After I leave this room, you will, under no circumstances, mention this to a living soul – not even me. Am I making myself clear?"
"Crystal!" Superman immediately uttered while eagerly nodding.
Batman reached his arm to the door, locking it with a sharp click while keeping eye contact with the naked hero.
"Then let's get to it" he added in that same strange voice as he pulled back the cowl, unhooked his cape and joined his friend on the cod.