She acknowledges his presence! A step forward!

Well, she has responded to him before, back when he ran across her at the convenience store, but that just amounted to her answering his question. Whereas here she actually seems to be taking some degree of initiative by offering him a pocky stick.

You can't belive how happy I am! She shows that she's not indifferent after all! An amicable action, hooray!

Hopeful as it may be, I actually think she will win at the end. The author has HER as their profile picture, and if you ask me, even if it seems one sided, I think she is the one "closest" to the MC, even if they don't interact too much. She is the one he spends the most off time with after all(time outside of class, which is mandatory). I mean they live close, frequently meet in day to day/night life, and even prefer to eat at the same place. And it might just be how I feel like, but time you spend with someone outside of your forced daily schedule will always feel more special. He even dreams about her.

I hope this emergency staircase can become their "happy place" where they can chat and kick back and relax.