Sora really had NO idea what had gotten in to him, but when he saw that window of opportunity when Kaito went off to play video games, Sora went out. No, he really didn't have an aim in leaving. It was just time for Sora to go out and not worry about everyone else and his little 'plans'.
How this ended up with him in the karaoke bar, no one knew. Maybe it started with him rolling through the door? That could have been anyones starting guess. Maybe, just maybe, after he was 'paid' and situated he took a seat and started ordering drinks. What could be better than a gimp who was trying to get himself drunk. Sadly Sky knew himself better than that. With the wonder if what Kaito would get himself into and what his brother could possibly be doing, he knew better than to fully inebriate himself.
Yet... sitting there... and watching Matsuda sing possibly the gayest song he could have started to hear himself with the exception of a few others, He was starting to feel the need to just get himself fully wasted.