Frown. "Can I give her some of my... Energy, I guess?"

"...Maybe. I'm not sure how, but... You might have a sense..."

"A sense..." Just... Go by what feels right, maybe? The way those words she spoke earlier, the attack she used, felt right... 

She steps up to Sailor Moon, reaching out for her hand.

She can be normal about holding a cute girl's hand. It has nothing to do with the length of her skirt.

Mercury's hand is warm, and a blue light spills from her skin. "Mercury, swift messenger of the Gods... Carry my wish to Sailor Moon!"

Something passes between them, a powerful thrum, and an answering light rises in Sailor Moon. She doesn't feel tired at all – and with that light comes a spark of an idea, almost a memory, and suddenly she knows the right action to take, here –

"Moon Tiara Stardust!" It just feels right, and she throws her tiara at the students and this time instead of turning them to dust-

Sparkling moonlight falls over them. They all sit up, several rubbing their heads or looking around. "What... What happened? Did I fall asleep?" one asks. 

"It's not healthy to spend too long looking at a computer screen! Remember to take appropriate breaks. You only have one youth, so don't spend it all on your future!"

"Ah... I spent so long studying..." The students blink, hazily, some looking at each other. "I didn't take any breaks," another murmurs. "We should go outside," another says. The students stand, and they seem totally fine, though they're now ignoring the presence of the Sailor Guardians (and the damage to the room) as they start chattering with one another as they leave the room. 

Sailor Mercury is staring at Sailor Moon, though, her eyes bright.

"...What?" she says, a little self-consciously.

"You're right," she says. "I've been so worried about 'tomorrow,' but... If I have you, as my ally... It's strange, but you make me want to believe that I'm already strong enough to face the future."

"Oh. Well. Good."

Smile!

...Then, awkwardly: "We should probably get out of here, now that everyone's alright... I'd like to talk more, too, about the Sailor Guardian stuff? And what that monster was?"

"Right. You can come back to my house, if you want?"

"I'd like that."

Then back to Erika's house. She can introduce Mercury to roof-hopping on the way.

She takes to it very well! She's also apparently faster than Sailor Moon – she starts to get carried away with running a couple of times, before forcing herself to wait or slow down.

Seems she needs more practice.

"I was in the track and field club until last year," Mercury says with a small laugh after the third time she accidentally pulls ahead. "I'd assumed focusing more on studying would mean being out of shape, but even though I'm a little tired from that fight... I don't feel that at all here."

Luna, on the other hand, is trying to resist the urge to pant (or ask to be carried). "Mercury's the swiftest of the planets," huff, "So I'm not surprised."

"Being a Sailor seems to give a pretty good bonus to your physique generally. I'm not nearly this strong or dexterous when not transformed."

"I'll try going for a run tomorrow, then."

"Have fun with that."

Hm, does the archery club have to do running...? Eh, that can be a problem for Future Erika.

"I will!"

They arrive at Erika's house shortly after. "Should we transform back?"