This is how Rarity and Bumblebee vs. Optimus and Twilight goes in My Little Pony Transformers: The Last Knight.
[Suddenly, two more Cybertronian Knights appear]
Cybertronian Knight: Protect the staff!
[As they fire and another knight comes out, something kills the Knights, and it is revealed to be Twilight and Optimus]
Optimus Prime: We've come for that staff.
Twilight Sparkle: Now hand it over.
[Everyone looks on in shock]
Nighlock: Optimus. Twilight. Hey, what are you two doing? It's me! Anthony! We fought together!
Optimus Prime: I fight for my own kind now! My own planet!
Twilight Sparkle: I fight for Cybertron only!
[Bumblebee and Optimus face off]
Optimus Prime: I am Nemesis Prime! You are nothing!
[Rarity and Twilight face off]
Twilight Sparkle: I am Nightmare Sparkle! You are nothing!
[Rarity gets out her magic hammer]
[Bumblebee hits Optimus in the face with his hammer]
[Rarity hits Twilight in the face with her magic hammer]
[Bumblebee then stops Optimus' blade]
Bumblebee: I-I am Bumblebee... your oldest friend! Optimus... I would lay down my life for you.
[Optimus' optics turn blue again]
Optimus Prime: Bumblebee. I have not heard your voice since Cybertron fell.
[We see Rarity trying to talk to Twilight]
Rarity: Twilight, I will always be your friend.
[Twilight tries to bring her horn down on Rarity]
[Twilight sees Rarity has stopped it]
Rarity: I would lay down my life for you, even to avenge you.
[Twilight's eyes transition from red to purple again]
Twilight Sparkle: Rarity. I don't know what came over me.
[Twilight backs up]
[Optimus drops his sword]
Optimus Prime: What have we done?
Twilight Sparkle: How could we possibly fall for his?
[Bumblebee pulls his parts back to him, putting himself back together]
[Megatron suddenly attacks with Nitro Zeus, Starscream, and Omegabot]
[He knocks down Optimus and Twilight]
Starscream: You both will die for your insubordination!
Omegabot: You have failed us all!
Nitro Zeus: You blew your chance to kill Unicron!
Megatron: Quintessa, the most ruthless of our planet, knew you couldn't do it. She knows I'm strong and you're weak.
[He steals the staff from them]
Megatron: You turned your back on Cybertron. Now you will watch Equestria die.
[They fly off as a Cybertronian knight comes out and punches Optimus and Twilight]
Cybertronian Knight: You betrayed your own kind!
[Some Predators begin attacking Twilight]
[One Predator punches Twilight, knocking her to the ground]
Predator: You betrayed your own kind as well!
Cybertronian Knight: You've chosen the wrong side!
[The Cybertronian Knights and Predators continue their attack on Optimus and Twilight]
[Nighlock looks on in horror]
[The Cybertronian Knights and Predators continue attacking Optimus and Twilight]
[We see Cogman and Ms. Cheerilee come out]
Cogman: Not going so well.
[Cut back to the attack]
Cybertronian Knight: Quintessa is the Great Deciever! [strikes Optimus with his sword]
Predator #1: She put a spell under you two! [strikes Twilight with his spear as another Knight strikes Optimus with his axe]
Nighlock: Get up, Optimus! Get up, Twilight!
Optimus Prime: [sadly] We can't. The Knights and Predators are going to kill us.
Twilight Sparkle: [sadly] We gave them a heck of a run, didn't we?
Cybertronian Knight #2: And the judgement...
Predator: Is death!
[In slow motion, the Knight and Predator prepare to finish off Optimus and Twilight. Just then, the Talisman activates as Nighlock then uses Grundir, the Spear of King Solar Flare. He blocks the strikes from the Knight and Predator]
[The Knights and Predators raise their weapons in respect]
Cybertronian Knights and Predators: Save us brave warrior.
[Nighlock puts the spear down]
[He turns to Optimus and Twilight]
Nighlock: You two have gotta get up.
Optimus Prime: We have failed you all.
Twilight Sparkle: Now many will die.
Optimus Prime: Equestria. The only place where its species let me call it home.
Twilight Sparkle: My home planet. Gone. Because of us.
[We see Cybertron getting closer in the background]
Nighlock: I know you both feel really bad for what you've done. But if we don't stop this now, there's not gonna be an Equestria left. We can't do this without you.