The moment Riku arrives at Merlin's house, he's whisked away by Yuffie and the others to help on a Committee job. The snow has begun to pile up, and the people of Radiant Garden need help to clear it out, especially from the roofs.
Even Riku would admit it to be an extremely dull job. The use of magic is completely banned due to how it could react to the snow.
"Come on, even I know that Blizzard or Fire magic could be bad, but couldn't, y'know, Aerith cast an Aero spell or something?" Yuffie groans as she lazily moves her snow roof rake.
"I don't like this job either, but I don't think creating a miniature blizzard would be a good idea," Aerith responds, clearly putting more effort into it than Yuffie.
Yuffie stops, confused. "When did I say to cast Blizzard? I said Aero-"
Aerith sighs, but lets out a giggle nonetheless: "No, I mean 'a blizzard' not the spell."
"Oh." Yuffie continues to rake the roof, distractedly, and accidentally covers Leon in snow. "Oh my gosh, Leon I'm so sorry! Please forgive me-"
Leon doesn't even move, standing there completely dumbfounded, until Aerith and Yuffie run to him to help him get the snow off. Afterward, he goes inside to change and warm himself up for a bit.
Riku, who has completely tuned them out to try and get his work done faster continues until he's completely cleared out his designated patch of roofs.
"Woah! Way to go, Riku! You work fast!" exclaims Yuffie, walking up to Riku from behind, deciding to shove her icy-cold hands onto the nape of his neck.
Riku yells "Yuffie!" with an irritated sigh, he says, under his breath, "Maybe you should, too."
"What?" Yuffie blinks.
"I said, maybe you should work fast, too," Riku says, agitated, moving onto Yuffie's section of roofs to clear them out for her.
"I- Wait, I can do it!" Yuffie trails behind him.
Ignoring her, Riku continues, "We could've been done by now, and I- we could be working on the data right now."
"I just thought some air would be good for us-"
Riku inhales and looks like he's about to retaliate until Aerith interrupts him: "This is about Sora, isn't it?"
"When is it not about Sora!? This always happens, but this time, I don't even know where he is!" Riku breathes heavily, trying to calm himself down. "I- I'm really sorry. I'm sorry, Yuffie. I'm sorry, Aerith. I'm sorry for snapping at you. I... need to go home."
Without waiting for a response, Riku leaves.