Actually my version of the theory might not be accurate but every theory is different .( sorry, why Namjoon put a lollipop in his coffee is not explained in this theory because I have no idea why )
Other members imaginating that Jin is there with them part 2
Jin is seen driving the truck at first, as I mentioned in the previous chapter. But when they all got on the backseat we could only see Yoongi,Hoseok,Jimin,Taehyung and Jungkook in the backseat (see picture above)-Namjoon is the one driving. The members are only imaging that Jin is there with them.