Steve
He leapt off the couch. The kid he'd met in the cemetery had somehow made it into the tower without setting off any alarms, announced that some girl was alive, that some camp was under attack before passing out from a variety of wounds that were seeping a concerning amount of blood. Percy looked paler than a sheet, but his entire demeanor had changed.
Percy practically flew off the couch, his posture changing from relaxed to alert and battle ready. Banner followed him to the kid, dark eyes already assessing the situation. They rest of the Avengers followed nearly as quickly.
But when they reached the passed out teen Percy picked him up, keeping the team away from the kid. He turned and started to walk down the hallway towards his room, muttering to himself.
"Percy you've got to let me check him out. He's covered in blood. Percy. Percy!" Banner was insisting, rushing to keep up with the younger man's quick pace. Percy just clutched the kid tighter to his chest and walked into his room, the door slamming and locking it in their faces. Tony raced towards a computer, pulling up the security feeds just in time to see Percy put duct tape over the cameras as his friend lay lifeless on the bed.
"Break the door down." Steve ordered, his voice tight. Tony looked pained but didn't argue. Thor looked resigned and stood back as Barton and Romanoff brought in a small battering ram. They counted down and slammed the door in.
Steve was shocked to find the room empty except for the bloodstained sheets.