I am so in love with the idea that Alejandro said that his was just an impulse to see Nora. His impulse was to please her because he wanted to see her as soon as possible too and because Nora felt the same way.
I am also in love with the way he speaks with her. He was worried about her, continuously asking if she is actually fine, caring for her. The moment that she asks if he wants to come up to the party, she looks unsure and maybe disappointed in the prospect that he might say yes and eventually get less time together. When he says that he came just for her, it just kind of confirms her that he does care and wants to spend time with her as much as she does. When she runs to him, she was running to her safe place when she is constantly cared for and loved.
