Here is how entering the school, meet Human Fluttershy, and Major Malfunction's dark past with Flash Fire goes in Code Red's Adventures of My Little Pony Equestria Girls.
(we see Twilight running on all fours with Spike on her back until she's see another human walking on two legs and walking his dog)
Spike: I don't think that's how the new you is supposed to walk.
Red Smoke: Ya think?
Dog:(looks at his owner to carry him on his back)
Owner:(points his dog to go)
Twilight Sparkle:(gets up on her feet uneasily)
Light Ultron: That's more like it.
Twilight Sparkle:(stumbles along) Come on, Spike, Sunset, and Code Red. The sooner we get my crown the sooner I don't have to use these.
Spike: Well on the bright side, you don't have to worry about those wings anymore.
Twilight Sparkle:(tries to use her magic) My magic, it's not working.
Spike: Makes sense. You don't have your horn.
Air Strike:(rolls his optics) Now he tells her.
Twilight Sparkle: What?!
Firestar: We really need to find you a mirror.(pushes the door open)
(everyone goes over to a trophy case)
Twilight Sparkle: What do ya think Spike? More artifacts he's stolen from Equestria?
Nighlock: No. They are achievements the students have done.
Twilight Sparkle: Oh.(gasps when she sees her reflection) What am I?
Air Strike:(from behind her) As Sunset Shimmer said, a human.
Twilight Sparkle:(squeals in fright)
Sunset Shimmer: Seriously, how does he do that?
Code Red:(Shrugs thier shoulders)
(bell rings)
(scattered conversation)
Twilight Sparkle:(gets knocked over)
Sauron: This can't-
Indominus Rex:(glares daggers at him)
Sauron: Nevermind.
Flash Sentry: Whoa! You okay?(helps her up and walks away)
Spike: I don't think this is a castle.
Deadpool: Clearly, you've been living under a rock this whole time.
Twilight:
I've never seen a place
That's quite like this.
Everything is turned around
This crazy world is upside-down.
Getting on my feet
It's the hand that I was dealt.
But I don't have much time with them,
Got to learn all that I can.
They don't use any magic or fly with any wings,
I don't get these funny clothes, skinny legs or tiny nose.
Everything's confusing when it's so new,
But I look a little closer and it feels familiar too.
What a strange new world (what a strange new world)
I'm trying to make heads or tails of this strange new world (what strange new world)
Sorting through the small details of this strange new world.
What a strange new world.
Human Fluttershy: Oh, I'm really sorry. I-I just found it, and-and though I should give it to her. I didn't know you had dropped it.
Flash Fire: Well, I did! And I was about to get it before you swooped in and ruined everything! You shouldn't pick up things that don't belong to you.
Light Ultron: There's our target.
Red Smoke:(pulls up one of her sai)
Nighlock:(stops her) Not yet.
Human Fluttershy:(hushed) It... doesn't really belong to you either.
Flash Fire: Excuse me.
Human Fluttershy: N-n-nothing...
Flash Fire: That's what I thought. It's as good as mine, and you know it. It's no wonder all your best friends are stray animals.
(enraged by this, Nighlock, Indominus, Red Smoke, and Twilight intervene)
Twilight Sparkle: How dare you speak to her that way!
Indominus Rex:(growls and unsheathed her claws)
Red Smoke: You're gonna regret that!
Nighlock: Take back what you said NOW!
Flash Fire: What did you say?
Twilight Sparkle: I said, "How dare you speak to her that way!"
Nighlock: Take back what you said to her now!
Flash Fire:(scoffs) You must be new. I can speak to anyone the way I want.
Red Smoke: Not here, you can't.(takes out her sai, surprising the students)
(all whispering)
Student1: Is that who I think it is?
Student2: No way.
Student3: It can't be.
Student4: That's Red Smoke of the Code Red.
Nighlock:(glares at her) Put them away. You're blowing our cover.
Red Smoke:(does so)
(luckily, he didn't hear the students)
Indominus Rex:(to Human Fluttershy) Are you alright?(turns to Flash Fire's direction) I'm getting a really-
Nighlock, Red Smoke, and Sunset Shimmer: Don't even think about it.
Human Fluttershy: I can't believe you did that!
Twilight Sparkle: We couldn't just stand there.
Red Smoke: Nope.
Indominus Rex: Not a chance.
Nighlock: It's not our style.
Human Fluttershy:(realizing it) Aren't you agents of Code Red?
Indominus Rex:(smirks) Guilty as charged.
Nighlock: All of us are present and accounted for.(points behind him)
Human Fluttershy:(sees the whole team, and notices Sunset is with them) Sunset Shimmer, you work for Code Red.
Sunset Shimmer: I'm a part time member.
Human Fluttershy: Well it's just that nobody ever stands up to Flash Fire.
Twilight Sparkle: Flash Fire?(looks back at him)
Human Fluttershy: You've heard of him?
Twilight Sparkle: Sorta...
Nighlock: And we were ordered to catch him.
Major Malfunction:(turns pale and falls over)
Nighlock: Boss?(runs over to him)
Sunset Shimmer: Mal?(runs over to him as well)
(they help him up)
Human Fluttershy: Is he alright?
Major Malfunction: I'm fine.
Nighlock: What's wrong boss?
Major Malfunction: Nothing. It's just that - that when he was my student, me and Flash Fire never got off on the right foot.
Everyone: (Gasps)
Twilight Sparkle: All this time and you never told anyone?!