I have not reread the chapter, but was it happen after their leader turned into dolls? Or probably after trebok caught them? Because tontata tribe is filled with simple minded creatures and Sugar's ability in making people's memories disappear might have something to do with it..
the plan was to knock out sugar with that tatabasco (fake grape). leo was about to put it in her mouth. usopp was happy about that because he thought he needs to put it in her mouth. Robin saw that Trebols accuracy is really good because he shot a little fly not just shot him, shot the fly between his eyes. Robin saw that with her DF, because she made a hand with an eye on it or so to see it better. then when leo was running to sugar she stopped him because she knew leo has no chance even though he is so quick. he took him back with her DF. somehow Trebol & Sugar saw him and the other dwarfs went to fight with leo but they had no chance. Robin couldn't just stand then back and wanted to help the dwarves, but usopp said this is their chance to run away. At the underground trade port, Robin used her Devil Fruit powers in an attempt to knock out Sugar with the spice the dwarves were going to use. Unfortunately, she let her guard down for a moment and Sugar touched one of her arms, transforming her into a toy. While wandering in the trade port, Robin wondered where Usopp went and put her hopes in him as well. everybody forgot about her and ussopp was like: WTF leo was about to really succeed with the plan but suddenly he didn't. and he asked himself why he's still there. Trebol hold down the dwarfs with his slime and then burned them all. and they all believed in their saviour and called USUUULANDOOOOOOO when they were half dead and that he will come to save them, but trebol just laughed about it and said there is no saviour, that everything was a LIE. Ussopp was already gone but heared them screaming from the loudspeakers. he was nearly out but then turned around and fought trebol & sugar but he had no chance. trebol cought him, sugar put the tatabasco in his mouth, believing it was poison and said: DIE. then his face turned reeaaally red and scary and sugar got knocked out because she was so shocked.