Alex Rider crossover - what's your secret?

Chapter 6

They entered the private lounge area where they were assigned to and saw Alex pacing around still with the briefcase. She looked annoyed and angry. They know they should leave her alone. They sat down as Alex continued pacing. Alex sat down on the ground as she started unpicking the cuff. She unlocked it and she opened the case. They couldn't see what was in it as she had the casing of it facing them. Her frown deepened as she saw what was in it. She slammed the briefcase shut and changed the password before cuffing it back to her wrist. What's in it? Why is it so important that she has to change the password and cuff it back with her?
She pulled out her phone and started texting until they were allowed to enter their private flights. Alex said goodbye to k-unit and followed NCIS to their flight. They sat around the flight but they were still able to see each other. Alex still had this energy radiating around her that no one dared to talk to her. She took the cuff off but hugged onto the case as she started reading the mission folders. Her eye twitched at one folder. "What's wrong, Alex?" Abby asked. The super brave soul. "... They want me to be a lady during the missions."
"Lady?" Abby questioned. "You know, wearing high heels, act like a girl, eat like one etc."
"So what's the problem?"
"The problem is I don't know how to walk in heels. I don't have any dresses. I don't feel comfortable in dresses or heels..."
"I'll help you." Abby said. "Me too." Ziva said. "We're going shopping!!!" Abby announced. "When?" Tony asked. "You aren't coming with us Tony." Abby and Ziva said in sync. Tony made a hurt face. "We won't feel guilty Tony. Don't worry." Abby said.
A lot of questions went through Alex's mind. Did MI6 know of my past? Did they know what the thing in the briefcase meant? Are they assigning me on that lady mission on purpose?