so basically, there are a lot of people who wondered why Jessica was bullied. well it's because she embarrassed Yoona in front of Donghae and Jaejoong, that's why Yuri excused them because yoona might cause a ruckus.(for she's not a good person when she's angry) that's why she wants revenge from the embarrassment, and she got a lot more angrier when her foot and back was hurt. because to rich people, their bodies are precious so she got mad after Jessica hurt her. and they can't stand seeing Jessica in their way and getting the two kingka's attention.
i hope you understand it already ^^

try re-reading :) 

Author's POV

Tiffany was walking across the hall. When suddenly she saw Sunny and Yoona running away while Yuri was trying to tell them something. Tiffany grew worried because these girls are rumored to be very bad girls and she was curious if they caused another thing because maybe it was all true. She hurried to the Girls Restroom and saw Jessica, all covered up in blood.
"ommo! Jessica-ssi!" she said as she redundantly shook her body. But Jessica didn't respond.
She called for help and found someone. 'Donghae oppa! Donghae oppa!" Tiffany said as she ran to approach Donghae.
"Why?" he raised a brow. "Jessica is all covered in blood!" Tiffany exclaimed. "BWOH?!" Donghae asserted. 
"She's currently dozed off in the girls restroom all covered in blood!"
Donghae rushed to the Girls Restroom and carried Jessica 'bridal style' to the infirmary.

Jessica's POV

I woke up lying down on one of the beds in a place that i haven't been yet.
"are you okay?" someone asked.
I tilted my head and saw Tiffany sitting beside my bed and changing the bandages on my right foot, arm, and hip.
"what happened?" i queered. "you seriously don't recall?" she curiously asked.
I tried to remember everything, but the only one that reappeared in my memories is seeng Yoona and Sunny... Wait! It can't be.
"perhaps 'they' tore me to pieces." I doubtfully said.
"Yes I think so too, because I caught them red-handed running away from the restroom, good thing I was the one who saw you." She sighed. "What caused you to be tortured by those queenkas anyways?"
"I really don't know (shrug) It's my first time meeting them and they started acting like that." I answered.
"ehhh! but they would never go wild like that, they never give attention to people who they think are useless UNLESS! If they see you as a distress to their own eyes." she explained.
"huh?" I raised a brow.
"You see, They are like the kingkas' bodyguards.They never leave their sides and they love to fish for attention. Once they see a nuisance, vengeance is served fully. and as I analyze, you are Donghae's maid BUT only I fathom that because of our encounter, so they may think you're his Girlfriend. For short, they're disgusted by your