Alex Rider crossover - what's your secret?

Chapter 5

Alex could be discharged in an half hour, which is when the drip finishes. Alex's phone rang after she answered Abby's question about the language. "What's up?" Alex answered it. "Alex!!!!" Tom screamed into the phone. Alex sighed as she put it on speaker. "Are you dead?"
"Sorry to disappoint you. I'm still alive." Alex said. "Hey! I'm serious dude."
"Yeah. I'm serious too. "Alex joked. "Anyways. How's that booty of yours?"
"Seriously Tom? Is that all you think about?"
"Nah. I think about your boobies too." Alex choked and she started coughing. Everyone started laughing. "Ah that hurts." Alex mumbled, bending forward a little. "Sorry. So... you still persistent about puberty not hitting you like a truck?" Alex pursed her lips. "Yes." Alex replied. "Dude. Have you seen yourself in the mirror? You so damn curvy and and SARAH!!!!! Explain to our friend Alexa why she should not deny the fact that puberty changed her!!!!!!" Sarah is one of the members of the Insane 4. "Is she on?" Sarah asked. "Yep." Tom replied. "Hey!!! You okay?"
"yeah."
"Can't you sound a little more like a girl?"
"I seriously have no idea how you want me to do that."
"A little higher on the pitch and maybe add a little more excitement and you're good to go."
"Nah. I give that a pass." Her voice does sound like a girl just not girly. "You still wearing your disguise?"
"How did you know?" The unit and the team frowned. What disguise? "How did you know?" Alex asked warily. "Because. I want you to take it off right now. AND. Take a selfie for us." Alex kept quiet, considering. "Alexa." Sarah said in a 'I'm serious' tone. "A cute selfie. stick your tongue out or something." Alex frowned, still quiet. "hurry up Alexa before we hunt you down and pull it off ourselves. take it with your friends if you like." Alex reached to the back of her neck and pulled off a wig and a hair stocking. She ruffled her hair bit before running her hand through her blond locks. Her hair is a little like Taylor swift's. "You look cute." Tony said. Alex glared. "Don't breath any word about it." Alex looks so much like a girl now. She gestured for them to come so they can take a selfie. They took it. Alex crossed her eyes. They laughed at that and then Alex sent it to Tom. "Oh my god... I think I just died... you're prettier than before!!!" Sarah exclaimed. "Sarah. Stop." Alex said. "Stop denying it. Come on. Be a girl."
"MI6 ask me to grow my hair."
"Why?"
"I don't know."
"I guess they want you to be a girl. Maybe it's for a mission?"
"Yeah... I had a suspicious feeling about that too."
*******
At the airport, Alex had her hair back up. They were waiting around. "Alex!" Someone called out. He approached. "Let your hair down from now on. It's an order from mr. Blunt." The guy said. Alex reluctantly did. She threw away the wig. "Better?"
"Yes, now here's your mission files." He said handing her a stack of folders. Alex flipped through the folders looking at the brief summary in the front that was crypt, only she, mr. Blunt and mrs. Jones know the the way to solve it. Alex slapped one folder back to the guy. "I. Am. Not. Doing. That." She said, punctuating each word. "But you're the only one that can do it." Alex scowled and turned around. When she took two steps the guy suddenly said, "Alexandra Victoria-"
Alex stormed back and pushed her face close to the guy. "Say anymore and I will shoot you." Alex threatened. Only NCIS and K-unit heard the threat. Why is she so angry?
Alex grabbed the file and started walking again but the guy stopped her. "Take this too."
"I'm not taking it." Alex said. "But-" Alex still had her back turned but she has already stopped walking. She raised a hand and the guy immediately shut his mouth. Why? Alex stormed back and took the briefcase. She cuffed the cuff onto one of her wrist, so the briefcase is technically attached to her by the cuff. She scowled before storming off without the unit or team. She skipped the line and went straight to the front, much to everyone in the short queue's annoyance but when they saw the girl who just flashed the cover of her passport and the security officers saluted her and let her pass, they can tell she might be very important and she also has a cuffed briefcase with her which meant it must be important so they weren't as annoyed.
What did she show those security?