I don't get it. What's with the sudden kiss at the end of chapter 7???

To shut him up i guess??

Jay asked Arthur for a kiss in the previous chapters (believing that it'll help, as per the CMS theory). Arthur thinks that Jay is someone sent by overfall to fuck them up and that if he (Arthur) kisses Jay (thinking that it is what overfall wants, since he thinks overfall sent Jay to fuck them up and mess with them) overfall or Jay would stop interfering with their job — well, that's IMO based on the things I've read but could just be to shut Jay's ass. ╮(￣▽￣)╭