You broke a rule. 

I told you in my very first letter that you can't try to see me when I pick up and drop off our notes.  You think what you did isn't a big deal, but it is.  I have to evade heavily armed guards, Theo.  Every. Single. Night.  There's only a narrow window of time in which I can dash over to your door, retrieve your question, and get back to Francesca's hidden passage.  The guards are thorough, but thankfully they're also predictable. 

I have a small board to write on and a stack of paper I took from school stashed in the passageway; I sit on the steps in the dim light and write my replies to you.  Then I wait until the night watch is scheduled to patrol two floors below yours.  I rush out to leave a new note under your door, always hoping the guards won't diverge from their routine.

I cannot get caught.  We cannot get caught.  Now is not the time to start breaking rules. 

I mean, I get it, I do.  Honestly, I've wanted to see you face to face ever since the day I spied on you from behind those drapes.  We have to remain on task, Theo.  We can't afford a distraction and meeting at this point would be a huge one.

As for your latest question... due to your illicit doorway hovering, you don't need a picture of me—you saw me, didn't you?  The light was poor so you got no more than a glimpse.  That only occurred because as I fled, I turned around just long enough to make sure you weren't following me.  Our eyes met, though, didn't they?  I'm almost certain they did.

Do not do it again.  One more breach of our agreement and I swear to you, the nightly letters will stop.  This—what we're doing, Theo—is important to me.  However, so is surviving the month.  Maybe now would be a good time to point out that you went beyond trying to see me.  You actually called to me in an attempt to get me to stop.  Thankfully, you refrained from saying my name, but I still feel the need to ask: have you lost your mind?  You didn't yell exactly, though you were loud enough to be heard.  Did someone hear you?  Your mom, a guard, your father?

I hope you're sorry for what you did. This isn't a game for me and it shouldn't be for you either. 

One more thing, and then that's it for the night. Even if I was inclined to give you a picture of me, I don't have one. This is how it works: rich people get their pictures taken, poor people (as well as the secret heirs of insane dictators) do not.

We have no photographs to trade.  Do we really need them? 

I don't. Your image is with me always; even in sleep, I can't escape from that honey blonde hair of yours.  Your dream-self is a much better rule-follower than you are, by the way.  If dream-Theo shows up tonight during the few hours I actually get to sleep, I may wake up feeling more kindly towards the real-you tomorrow.