Zircon was right. She was right on so many levels.
Everything she said was true.
Rose had apparently been a wanted rogue long before the death of Pink Diamond. So how did she get past all of her other soldiers? What, they didn’t notice the wanted criminal walking to their leader?
How come the Sapphires didn’t use their future vision to warn her? Why didn’t her quartz soldiers or Agates try to stop her? It was apparently only her who was there. They all couldn’t beat her?
No chance in hell. The only way Rose could’ve gotten to Pink Diamond was with higher authority.
And Yellow Diamond knows it. That’s why she stepped in.