It was late. Well, it was hard to keep track of time while floating around in space with no sense of night or day. But there were clocks inside the ship that said it was just past midnight, and everyone was asleep so it must've been late. But Keith couldn't sleep, with everything going on during the intergalactic war against the Galra empire. With just reuniting with his mom, with the stress of everything piling up... Keith just couldn't fall asleep. He was tired, but his brain wouldn't stop rushing with thoughts. So he was up out of bed, wandering the dark halls that were only lit with those strange, too-bright sconces. It was easier for him to process things while actively engaging in some kind of activity. And if that didn't work, hopefully the physical exhaustion would catch up before it got too late.
As he was wandering the halls of the Castle of Lions, he heard clattering from inside the training room. Assuming it was one of the other Paladins, he paused. No matter who it was, it would be nice to talk or just have some kind of distraction. If it was Shiro, he might actually be able to get proper guidance and sleep easy. If it wasn't a Paladin, then it was a problem that was good to check out.
Keith pressed the button to open the door just in time for the rhythmic banging to turn into a crash as one of the lockers burst open and something--someone--tumbled out and onto the floor. It was dark in there, but there were those small lights on the walls never went out. It was just enough light for Keith to see that they had a stowaway. Whether that stowaway was friend or foe, he didn't know.