Perona chickened out, period. When the going got tough, she weaseled out and ran for the hills. Once Usopp defeated her, she tucked her tail between her legs, and bolted. Why didn't she stay and tough it out with Moria and the others when Oars was fighting? Every strawhat stays behind when things get tough, unless Luffy orders it differently (like that only time they actually RAN FOR it, on Sabaody)ā¦
This ties in to the correlations with Robin and Nami's situations too. Nami didn't run for the hills when she realized Arlong "betrayed" her; she tried to reason with everyone and say everything was going to be okay, only to realize that everyone had enough. And, when the other 4 SHs were decimating Arlong Park, Nami stayed to watch it all go down.
Robin helped Crocodile, this much is true. But when she betrayed him, she didn't run away like she did all those times before. She stood tall, attacked him, and when the end drew near, she sucked it up and accepted her fate, realizing her dream could never be fulfilled, and decided to stay in the tomb and die; But of course, not until AFTER she helped Luffy out by providing the antidote to Croc's poison.
In what way can Perona's situation be considered on par with these two? She didn't stay behind to help and/or watch everything go down; I don't think I remember her ONCE helping out any of her fellow comrades in dire times of need, actually. And, where could she be pointed out as "aiding" the strawhats in any depth or form when she was planning on deserting them on TB anyways (were she to actually steal their ship).
And even then, if she was truely committed to leaving Moria for good, why make any bit of mention of him ever since you actually LEFT him? She appears pretty regretful when she was shown to be at the castle by herself...