The library’s door suddenly burst open, and through it charged one cyan pegasus. “Where is it?!” Rainbow Dash demanded.
“Where is what?!” Twilight Sparkle answered. “Why’d you just-”
“The time machine! The one you just finished! Where is it?!” Dash was frantic now.
Twilight wondered how Rainbow even knew about the device. She tried her best to keep it absolutely secret; apart from herself, only Princess Celestia and Spike knew that she was even working on the project — let alone had a prototype. The unicorn decided that there wasn’t any point trying to deny it; if Dash knew, then Dash knew.
Twilight tried to calm her friend. “It is not a time machine. It simply projects your consciousness and will into your past-”
“I don’t care! I just need to use it!” The pegasus bellowed.
“I-” Twilight started, but then stopped, as she suddenly realized that there was only one reason Rainbow would want access to the device. Her expression became sullen. “You can’t help her, Rainbow Dash,” Twilight said sadly. “I know you love Pinkie, but she died saving all of us. If she didn’t, we’d all be-.” The unicorn couldn’t bring herself to continue.
Twilight’s sudden change of mood seemed to strike the pegasus. Landing next to Twilight, she spoke just a little more calmly: “I need to help her! She was my marefriend, for goodness’ sake! I should have been there with her! The only reason I wasn’t was that I didn’t know she would turn back. It was too late before I could do anything!” Tears now flowed shamelessly from Rainbow Dash’s eyes. “Please send me back there, Twilight. I could help her. We all owe it to her.”
Twilight put a hoof on her friend’s shoulder. “I can’t let you do that, Rainbow. It’s too dangerous. I don’t know how Pinkie stopped that thing, but it cost her her life to do so. I can’t bear to lose you, too!”
“You wouldn’t have lost either of us! We’d have beaten it! Pinkie and I could do anything as long as we did it together!” sobbed the pegasus. Her expression then languished. “And if we couldn’t, then at least I could’ve died with her. It’d have been better than going on like this.”
“Rainbow! Do you know what you’re saying?” Twilight was shocked at her friend’s despair. “I-I can’t, Rainbow. I just can’t-”
Rainbow Dash deflated even further. Still crying profusely, she now pled with a broken voice: “You can’t let that happen to us, Twilight! Not when you can change things! How could you know what it’s like? To wake up every morning knowing that you’ll never see her again. To never be at a party thrown just for you again? I still hear her voice every night, singing as if nothing happened! I’d give anything to hear her call me “Dashie” once more. To listen to utter nonsense again. To feel her touch again. I need her!” How would you feel if Fluttershy-.” Rainbow couldn’t continue as her voice was overcome by heart-wrenching sobs.
It hurt Twilight to see her friend in so much anguish — hurt so deeply that she wanted to give in and let Rainbow have her wish. She needed to try to return to a rational approach soon, or else she’d lose her resolve. “You’re right; I can’t know what it’s like. But we can’t go altering the timeline, especially for personal reasons. You have to-”
“If you don’t let me go, I’ll hate you forever.” Rainbow Dash abruptly cut in. Twilight's argument stopped dead in her throat. Rainbow's voice, as wretched and broken as it was just moments earlier was now like a blade of ice, cold and serious. The unicorn looked into her friend’s magenta eyes and saw only steel. These were not just words; this was an oath. She meant what she said with every fiber of her being. If Twilight didn’t help her, she’d take it to her grave and, quite likely, beyond.
Twilight’s resolve crumbled. Losing Pinkie was hard enough. She couldn’t lose a friend like that, especially when she could prevent it. Even the idea that she could be easily sending her friend to her death paled in comparison to that of Rainbow hating her forever. “Besides,” some selfish, idealistic part of her mind spoke up, “maybe Rainbow Dash can save Pinkie. Maybe you will see the party pony once more. Isn’t that worth the risk?”
Twilight had no further words. Closing her eyes, she sighed, nodded once, and walked towards her lab. Leading Rainbow to the device, she opened the door and motioned inside. “Go on, but please be careful,” she said, tears leaking from her eyes.
The cyan pegasus wrapped Twilight into a tight hug. For the first time in a long time, Rainbow Dash cracked a smile and hope shone in her eyes. “Thank you for this, Twilight. This means so much to me. Don’t worry — I’ll see you soon. Both of us will.”
After Rainbow stepped into the chamber, Twilight slowly closed the door. Reluctantly throwing the switch, she hoped and prayed to the Princesses that her friend would still be there when she opened the door again.