Given the progression of Peridot’s character over the series, I want to analyse what’s changed and what’s stayed the same since her first appearance and how those characteristics played out in the first two episodes of In Too Deep.
I’d like to point out that Peridot has always been logical, resourceful, and pragmatic, and brutally honest about that pragmatism. Those are her core values and those are what she values most when she’s assessing a situation. She makes decisions through accumulating information and deciding what the best course of action is based on that information.
When we first see her in Warp Tour,
Source: SU Wiki
It seemed cold and heartless of her to just step on the robonoid. But to Peridot, this was the logical conclusion. It was a robot, and it probably cost more to repair it than to just leave it behind. If anyone got a hold of it, they’d have an insight into her technology and she didn’t want to lose her competitive edge. To her, the technology on Earth, even the gem technology, is primitive.
In the same way, she may have appeared more heartless than Steven did in Gem Drill. Steven says, the Cluster doesn’t know what it’s doing. But Peridot replies, it’s going to do it anyway, and that’s why we have to use the drill on it.
But really that’s pragmatism talking. Peridot doesn’t see any other way to disable the Cluster, which is an immediate threat. We know she doesn’t want everything to be destroyed, and now that we’ve seen her character, we know that she’s not a heartless person who likes destroying things because they don’t work anymore. And it’s because her environment has changed, and the information she has of that environment has changed as well.
1. Peridot felt like a part of Homeworld
I think that we often forget Peridot didn’t want to abandon Homeworld at the outset. She felt like she had a place in Homeworld where she belonged and did her part. It was probably a small part, something along the lines of being a technician or an engineer, but it fell in line with her interests and what she was good at, so she felt at the least comfortable doing that kind of work. Part of the designated labour comes from the caste system on Homeworld. But Peridot is logical. In her mind: This is where my skills can be put to the best use, so this is where I’m best placed.
In It Could Have Been Great and Message Received, Peridot describes the Diamonds as the Deciders, and Yellow Diamond is the best decider of them all because of how logical she is. Because of this, we know that if something makes sense, then that’s what Peridot is going to be in line with.
Source: SU Wiki
Her weakness is that if she doesn’t have all the information, then whoever controls the information can influence her decisions. And this is what Homeworld has done. They’ve taken out information about the Crystal Gems, why they’ve rebelled, and why the war took place. They’ve even taken out the memory of Pink Diamond. In the new Homeworld Hand Ship, we see that the Pink part of the emblem was taken out. But in all the old things associated with Homeworld, we see the diamond symbol as having four diamonds, pink included.
Because of this, Peridot was at first fine with coming to Earth and checking on the Cluster, with the full knowledge that its emergence would destroy Earth. In her mind bank, Earth was a failed colony; it’s not viable. Had it been a successful colony, it would have offered gem kind many things, like a foothold in this part of the system, more gems in the population, communications and towers and all kinds of infrastructure. From what she knows, gems were denied all those benefits because of the war. She called Rose Quartz out on it. Her thinking was that if Rose wanted to help gems, why deny them of everything Earth could have offered as a colony?
Peridot owes her existence and even her technology to Homeworld. When she first arrived on Earth, none of the gems could recognise her as a gem. Peridots must be a young race and their existence can be attributed only to the shift of Homeworld towards new technology and allowing assistive technology such as her limb enhancers. Otherwise, she wouldn’t be able to hold her own in terms of size and strength. She says “It’s hard not to have feelings for where you came from.” And she doesn’t sound bitter, she’s sad. She wasn’t and then she was. It’s the same tone Rose used in Rose’s Scabbard when she asked Pearl if she wanted to fight. It’s the same voice Lapis had in Ocean Gem, when she was looking at Homeworld. With all the things Homeworld had done that hurt people, and Earth in particular, it must have done some good things for its people that would make them miss home.
But there were other reasons the war was fought. Individuality, choice, identity. Those things would not have been possible under Homeworld’s systems. And those were the reasons Rose decided to rebel. Peridot didn’t know that, and actually until now, I don’t think she has the whole story. She has realised though, that the organic life of Earth could still be valuable to Homeworld. That was exactly what she was trying to tell Yellow Diamond. It’s a costs-benefits analysis and if YD were logical, she would have agreed with Peridot. And this is where Peridot disagreed with YD. And she tried to convince her, and she tried to explain things in a logical way, because in her mind, YD is rational and logical and she should know what Peri is talking about.
Source: SU Wiki
The moment Peridot decided to rebel wasn’t a moment when she just told herself “Ah yeah, Homeworld is evil and the CGs are totally good guys and I should join them.” The other thing about Peridot is that she’s brutally honest, and just because she was faced with Homeworld’s most powerful figure, she wasn’t going to let it stop her from giving out the diagnosis that YD wasn’t being logical, wasn’t being practical and pragmatic. And then Peri got frustrated and called her a clod.
So I don’t think her reform arc was rushed in any way. It was the natural progression that upon receiving new information (and Peridot gathers information fairly quickly when given the chance) she would make a decision. Throughout the series she never said she hated Homeworld. She was trying to find a way back, as in Cry For Help. When she called YD, she did it because she realised the CGs couldn’t save Earth and terminate the Cluster on their own, but Homeworld, with an entire empire of resources, probably could.
And the biggest indicator that Peridot doesn’t just hop into things because she likes or doesn’t like them is the next point.