Ah, so Makube went to college simply because Nimura-sensei was a kind guy who asked him to enroll in his college!
It seems even before, Makube and Kizaki had a rivalry. Makube simply wants to help people, while Kizaki wants to be a good student to Nimura. Iruko's just there to make sure Makube doesn't get into so much trouble because she loves him! She also doesn't want him to get any girlfriends so it makes sense she helped make his pretty strange look! That look she had was creepy though...
I feel sorry for Miss University Student. She existed as a punchline for Nimura-sensei's last words... Ah well, Kizaki was interested in her. That might not be good for her though.
Nimura has some very profound words about college! It exists as a place where you can fail? I sure do hope that's right.
Girl, if you didn't like his new haircut and tattoos. That's your loss
Nah, Makube just rejected her AFTER this. She was probably just surprised at his new look.