Lalli isn't the best at understanding other people. He's a bit self-centered when it comes to how he relates to others, applying his own personal motivations to other people's actions in an effort to understand them. It doesn't always work, because Lalli's thought process is...odd, to put it gently. And those misapplications of motive lead to many misunderstandings, both humorous and not.

In this case, though, Lalli isn't too far off the mark. He can see Finnick walking briskly and attempting to escape, and it reminds him of how he himself often tries to escape conversations. So in Lalli's mind, Finnick doesn't like the game and wants to leave as quickly as possible. Completely understandable, Lalli himself also wants to escape this situation.

"It's telling you that you've eaten too much sugar." A straightforward answer in his mind. Humans aren't made of sugar, they're not baked goods. So Finnick must have eaten too many cupcakes recently or something. But after saying that, Lalli will wordlessly point to one of the side passages out of the room. He's already scouted out several different escape paths, so he might as well share his knowledge with someone as similarly annoyed as he is. Especially since he plans on using that same path for a quiet escape shortly.

Lalli's sign, for what it's worth, says 'NEVER SLEEPS'. A fair assessment, if an annoying one.