He wants Luffy to save them because Saturn is far stronger than he is.
Wait this doesn’t make sense… Is Saturn stronger than Kizaru just because or is Saturn stronger than Kizaru Because Kizaru has just fought a Yonko like 5 minutes ago and was fucked yo by that AdvCoC
it’s one or the other… You can’t prove that Fresh Kizaru is weaker than Saturn here
Either it’s Kizaru wants Luffy to beat Saturn because he doesn’t want to lose his job so he’s pretending to be down while helping Luffy… Or Kizaru wants Luffy to beat Saturn because he is NOW too weak to do beat Saturn since he just got fucked up by Luffy
these are the only provable Situations outside of Oda just having someone directly say “Saturn > Kizaru” which Oda never has characters just directly powerscale shit like that
so yeah as far as we know
1. Kizaru doesn’t want to show that he’s helping Luffy so he doesn’t want to actively betray the government and like leave the marines or something
2. Kizaru has an unknown amount of strength that he’s hiding. Maybe it’s just enough for this collecting food thing, or it’s actually enough for him to really fight but weaker than Saturn, or it’s enough strength to even beat Saturn but all he wants is for Luffy to do it without anyone knowing he’s involved