There had to be some sort of correlation between being alone and him freaking out.
On any day, he could be alone, content in the knowledge that Tony was off building new suits in the lab below, Steve was learning the wonders of modern culture, Clint was… somewhere in the vents.
He knew that at any moment, he could wander up to the common room and find Natasha there and they could watch Gravity Falls and eat Twizzlers.
But currently, every Tower resident was off at various meetings and Bruce was totally not freaking out.
“Dr. Banner, current readings show an elevated heart rate. May I suggest engaging in a relaxing activity?”
Bruce blinked away from his computer screen. He wasn't sure when analyzing data had turned from boring to stressing.
“Is anyone available? To, um, to watch a movie? Or something?”
“Oh.” Bruce bit his lip. That shouldn't make him this anxious. He was an adult, not some dependent child. And yet?
“Is anyone going to be back soon?”
He wiped his hands on his legs. “Okay.”
So he maybe exaggerated his lack of freaking out.
Bruce had attempted to keep working through his solitude, but it hasn't gone well.
Panic had risen and now he was pressing his back up against a filing cabinet, hands shaking, fighting against the green in his veins that only wanted to protect him from the hit that both perceived to be coming.
“Dr. Banner, please listen. The sun is getting low. You are very safe. The sun is setting, as it is 8:27 PM.”
J.A.R.V.I.S. repeated himself, his words only became more distant to Bruce.
“Hey, big guy.”
Bruce's eyes snapped up, breath slowing minutely. “Nat?” he asked hoarsely.
She smiled sadly. “I think we need to teach J some better soothing tactics, huh?”
Bruce nodded shakily, his breath evening out at the presence of someone safe.
“Let's go finish up our Gravity Falls marathon, yeah?”