I think the main crux of it is that Rayla is both an extremely rational (pragmatic) person and a highly emotional one. Is she thinking everything through rationally? Not really. It’s a feeling, one that she can’t ignore, much like how she had to turn on Runaan really in a matter of seconds to defend the boys. We’ve also seen Rayla put that sense of what’s right over the mission early on in 1x03 with offering to go back into the tower with Callum, and just like in 2x07, he doesn’t have the same instinctive impulse. After all, if they’d gone up to the tower, it easily would’ve been a disaster, and likely left each of them dead in the conflict and Ezran, the Egg, and Bait on their own, and Rayla knew all that on some level, yet she offered anyway because of the “I couldn’t live with myself if I didn’t” that exists as part of her.
Rayla thinking fast and emotionally isn’t a mark against her. Her response to Callum’s concerns shows remarkable maturity of stating that this doesn’t have to be his choice. And Callum, in many ways, can be just as dedicated to the mission as her, hence why he does stay on track in this scenario (”Then we need to get to that tree, even if it takes all night,” “Rayla’s right. We can’t go home yet. The mission is too important”). The only times he isn’t 100% focused on it is when it comes to convenient, on the way detours related to his magic (ie. 1x04 with the Lodge and the Cube being something they’d have to pass anyway, Lujanne’s feels safe and they’ve already been there for two days, in 2x04 they’re caught in the storm no matter what, etc.) or slowing their progress because he’s putting her first (pushing the boat away for her comfort in 1x05, offering to go around the sea in 2x04, going after her in the above scenario).
She has a streak of brave and noble and stupid in her (hello, Gryffindor) that doesn’t always bow down to reason. She’s focused on their mission and with keeping the boys on track, but she also always gives into whatever detour Callum wants because there’s that emotional base just as much and she’s fond of him. She’s also willing to sometimes put her comfort/desires ahead of the mission/the boys without being willing to tell them why, either (ie. not wanting to take the boat at all and having to be cornered into it, insisting in taking tougher aka slower terrain).
Rayla is a character who both has a strong sense of the right thing to do, but struggles with carrying it out immensely, and this is something Callum calls her out on in 1x02: “Why? You know this is wrong” and all she can do is deflect, “An assassin doesn’t decide right and wrong. Only life and death.”
As for her not telling them about the Moonstone Path, that’s always something that’s given me pause, too, but again: this decision is made and carried out in a matter of minutes. That’s not to knock it, but it makes sense that she would even have the time to be thinking everything through.
Rayla’s development in this scene, and that she sees how the dragon fits into a cycle of violence, is largely because of Callum, and once he sees that too, he immediately wants to go with her as well: “You’re right. If we’re really going to change things, we can’t just watch while humans and Xadia keep hurting each other. But how do I take a stand? Believe me, I want to go down there with you and be the heroes who stop all the fighting.” But unlike Rayla, he feels completely incapable of making a difference.
Basically they’re multifaceted characters and can be contradictory like anything or anyone else, but I do always think their core motivations and decisions make sense; that doesn’t mean they’re not sometimes also messy.