Whilst everyone is fixated on that ending with Big Mom arriving at the prison and the Killer reveal, no one is talking about how Chopper, Momonosuke, Kiku and Tama are there with Big Mom as well.
I actually want to talk about the fact that Chopper is there with them. We know Chopper wants to cure all illnesses and with this SMILEs dilemma Oda is very smartly introducing motivations for various Straw Hats including Zoro, Sanji etc..
I think the next person who will be affected by this SMILEs situation will be Chopper as he is the only Straw Hat who has no idea about the effects of the Smile Fruit so far. Remember how mad he got when he realised how Caesar’s gigantification experiments were affecting the kids on Punk Hazard? I think this will make Chopper equally mad, even more so when he realises it’s the work of Caesar.
I theorize that, after Chopper takes a look at Killer, he will try to help him and that may push Kid to trust Luffy somewhat.
*Theory by ArzanishShumak