I want to say yes and no?
No, because it's the common room - you can't freak out about people being in your space, when you are in a public place.
But also yes, because Torulf was being inappropriate.
But also no, because it's weird to be possessive of a friend like he's your boyfriend.
But also yes, since Mikko and Arvo's relationship is complicated and they kind of were flirting, just in their own low-key way. Which means Torulf was actually stepping on Mikko's game and that's a major faux pas.