Fedya just freaks out, probably nothing would calm him down in a moment of panic. Even after the said trouble is resolved he'll keep panicking over the thought of "almost getting in trouble" for the next few hours.
Anıl just tries to think rationally, accepts when he's in trouble most of the time. Doesn't beat himself up over it but he's not going to be cheerful or anything like that either.
Erina keeps herself busy, she usually doesn't get in trouble though. Tending roses or talking to others will most likely cheer her up.
Boris would only ever cheer up with Fedya's company.
Gaia also would only cheer up with Yelena around because she was her first and only friend, so now she doesn't really have anything to cheer herself up with. When she was younger, before she even met Yelena, the thought of being a good person Matthias would calm her down & cheer her up though. But now she also doesn't trust Matthias, so...
Matthias simply doesn't get in trouble.
Zümra also thinks about her family and it'll keep her calm for a while.
Yelena is mostly a cheerful person anyway, she didn't let her troubles affect her that much - at least before Matthias.
Kemal likes to isolate himself and it helps.

As you can see, most of them feel better with someone they trust to keep them company :]