He's shocked

“I don’t know, Taylor. I don’t think that…WAIT! HOW THE HELL DO YOU KNOW THAT NAME?” Zack startled.

“Really Zack? You and Gavin have been calling Hannah that for years. Did you two knuckleheads really think you could keep that name a secret forever?” Taylor replied.

“Well, no, but we figured that you wouldn’t know about it for a long time! How long have you known?” he asked.

“About three years. I overheard you guys one day when you were playing your video games. You two tend to get a bit loud when you’re pretending to blow shit up!”

“She’s not mad about it, is she?”

“Hannah? Mad about that? HELL NO! Actually she’s quite flattered by it. She blushes every time I bring it up,” Taylor informed her little brother.

“Bullshit! Nothing could make Hannah blush!” Zack said as he refilled his bowl.

“I’ll prove it to you later, but for now, finish eating and join us.” Taylor said before heading back out onto the deck.