[He nods quickly in agreement with her saying how easily this day will be remembered. And then the phone buzzes - as she starts to excuse herself, his smile fades a bit but he's quick to assure her.]

Of course! I don't wanna hold you up. I'm happy that you had this much time to spend with me! [She's clearly a busy woman, so every moment with her feels like a gift.]

I- I'll be sure to text you! [He probably won't forget. In fact, it would be surprising if he thought about anything else for the rest of the day! He holds his phone close, like it's a sacred object.]

...Thanks for keeping me company, Daisy!