I guess at some point, Kirito (Matsuoka Yoshitsugu) doesn't really want to be alone. He's a solo player because he's probably not good at dealing with people. I know the feeling. I don't now how much more we'll see Kirito like this but other than his 'bad guy' image in ep2, I guess that's the end of it…
'Bad guy' Kirito isn't his true self so I guess that's why we see how nice Kirito really is in this episode but at the same time, we also see him continue to hide his true knowledge about the game from other people. First off, I was really surprise to see Kirito join a guild. Although I guess that just proves that he's not entirely into being alone. Also the effect of loosing the entire guild members all at once made a huge impact to him. How much impact did it made? The Christmas Event practically showed just how much he wanted to protect everyone. It's not about being a beater or whatever. He probably just wants to have real companions or whatever. Anyway, the reason he probably hid his real level (and strength) was probably because he wanted to fit in with everyone. That's the best reason I can think of… or is there a better explanation for it?
I know how it feels adjusting to a new environment, getting used to people and such. Everyone practically knows that. When Kirito joined the guild, it was probably a difficult adjustment since everyone at the guild already knows (and personally knows) each other. It's a difficult fit. I believe that he's not entirely comfortable with them that he didn't even had the guts to at least stop them from the dungeon exploration without their leader, Keita. After their death, it's no surprise that he's blaming himself for everything since he was the only one who survived. In fact, he was the only one strong enough to survive that trap. As each members die in front of him ending with Sachi's (Hayami Saori) death, he hated himself. The rumor about the rare item on the Christmas Event became his hope of actually at least reviving Sachi to hear her thoughts about what happened. Although he's not entirely attach to them, going back to being alone is definitely difficult. But at the same time, joining another guild might also be difficult for him because of the trauma. Whether Kirito decides to go emo over what happen or move on and find another guild, partner or whatever would be something I would definitely like to see. I'd like to see how Kirito will develop as a character, a player and a survivor of the game.
On a final note, I'm really happy to see Klein (Hirata Hiroaki) again in this episode. He now have his own guild with probably his friends from real life. Their meet up at the Christmas Event showed that he'll probably do anything for Kirito and I'm a bit disappointed that Kirito decided not to join Klein's guild. Although it is understandable that Kirito didn't join them (for now), I'm still hoping that he'll come to his senses and actually join Klein and his friends.