Weiss, Ruby, and Blake were all spending time in the room doing their "normal" activities, baking, reading, and the such when a young girl stumbled into the dorm. Surprised as to how, Blake was the first one to react, walking over to see the child was similar in appearance to Nora. By then, Ruby had put the cookies she was making into the oven and grabbed Weiss from her studies to see why Blake was suddenly so confused, then saw the bronze haired brawler in toddler form herself.
"I want to protect her, she's too precious!" Was the initial reaction from Weiss, responding to Ruby's "She could rip you in half, you know?" with a quick "Protect her emotionally you dolt, if what you and Jaune said was true, she would be mentally right after you know what happened."
Realizing her partner was right, Ruby looked ashamed and asked if Nora knew who they were. "No, but where's Ren, we need to leave soon!" Both Ruby and Weiss had no clue how to respond, so Blake stepped in. "You're at Beacon, one of the academies, and I'm Blake, now that you are both in a kingdom, we can help you find him." She wasn't looking to actually find him, assuming he too hadn't regressed, simply to stall out time until their friend was back to normal.
And so, RWB was dragged along by a three-foot girl who could most definitely kill them if she wanted to.