I started the manga two days ago and got to this chapter today.
Things accelerated so much these past chapters! Reality catched up, everything falls into place. It feels the manga is coming to an end indeed.
Heck, I even think this could make a perfect last chapter! IMO, leaving the ending open could be very good.
I'm feeling kinda sorry for Harima, too.
As for the smile Karasuma drew, I don't find it weird, quite the contrary actualy, to me it's absolutely pure and full of emotion, but hey, that maybe is me being overly sensitive. That scene was magnificent.
Really got a lump in my throat right now, ever since the 10 past chapters or a bit more, and the feeling grew worse when I saw the picture of Tenma smiling...