Developed in the comments from Part 16 — The Chase:

「 He saw a glare from the metal object hidden in her clothing. "Shit! That's a knife!" 」

ALTERNATE Part 17 — Psycho

Eventually, Zap reached Xin. Tackling her and knocking her down, he grabbed the knife in her jean pocket. "Hey!" Xin shouted, watching Zap run off. "Where are you going?!"

"Fuck you! I'm going to kill someone for you!"

"Wait, what?! Come back here!" Xin was shocked, not only because Zap said he was going to kill someone, but also because those words came from Zap. Xin got up and started chasing him down.

Once Zap reached Grace and Blake, he saw Blake with an assault rifle. Not worried, he brought out Xin's pistol and shot one of Blake's hands, causing him to quickly drop the gun and grab his hand to stop the bleeding. Rushing forward, he stabbed Blake's chest, right as they appeared in Xin's view.

Xin looked at Grace, then back at Zap, not sure who to focus on. Grace, in horror at the sight of her bleeding boyfriend, started running. Zap grabbed Blake's rifle and started shooting in Grace's direction. Eventually, she fell as well. Now with only Zap and Xin remaining, Xin wasn't sure whether to run or not. She started walking back when Zap said, "I took care of her. Are you happy now?"

"Huh?"

"I got rid of the bitch ruining your life, and the son of a bitch who was right by her," Zap said, breathing heavily. "Are you happy now? I killed two people just so that you wouldn't have to worry about them anymore..."

"Zap! You've gone insane!"

Zap aimed the rifle at Xin. "If you aren't happy, I don't think I need evidence—"

"Woah!" Xin said, backing up. "When did I say I wasn't happy? Now I don't have to deal with her anymore! But, Zap, you didn't—"

"You're happy? Great. Now, forgive me for fighting with you, and let's go back," Zap said, dropping the rifle.

"Uh—yeah." Xin looked at the blood on the knife Zap used to stab Blake. "Yeah, let's go back. Away from all this."

Zap started walking towards home. As he was side by side with Xin, he whispered, "Sorry about all this. I just wanted to make you happy."

(You know what? What if everything was backwards? What if Zap and Xin's roles were switched? What if Grace and Blake's roles were switched? How would this make you feel? Would change of character make the story interesting in a different way? Let's find out!)

ALTERNATE Part 17 — Psycho (Xin)

Xin managed to catch up to Zap. Grabbing the back of his shirt, she pulled him down. Grabbing his knife, she began to run towards the college.

"Hey! Where are you going?" Zap asked.

"Doing you a favor!" Xin yelled, hiding what she was actually about to do. "Thank me later!"

"A gun and a knife... come back here!" Zap quickly got up and started following Xin.

Once Xin reached Blake and Grace, she noticed an assault rifle in Grace's hands. Unfazed, she brought out Zap's pistol. Quickly shooting one of Grace's legs, she dashed towards her.

Grace fell to her knees, clutching the leg that Xin shot. She looked up just in time to see Xin as she quickly sliced Grace's neck, making her entire body fall to the ground. Zap had just arrived and saw the whole thing happen.

Zap looked at Blake, then back at Xin, not sure who he should be paying attention to. He focused quickly on Xin, who grabbed Grace's rifle. Blake quickly started running. Xin quickly started firing in Blake's direction. After a few seconds, Blake stopped running and fell to the ground. Zap started to run back when Xin asked, "Are you satisfied?"

Zap was confused. "Huh?"

"I got rid of the son of a bitch ruining your life, and the bitch that was right by him. Does that make you happy?"

"Xin... I don't think this was the—"

Xin dashed towards him. Now they were face to face, Xin's knife, bloody, at Zap's neck. "I don't have to make you happy. In fact, I could make you miserable right—"

"Xin! Calm down!" Zap said, grabbing the exposed part of the handle and bringing the knife away from him. "Look, I'm grateful for what you just did, I really am! But you just killed two people!"

"Yeah, and?" Xin asked casually, looking at Grace's lifeless body. "They were bitches anyway." Xin pocketed her knife and stepped back. "Anyway, sorry about our fights. Come on, let's go back. I need to wash up."

"Yeah," Zap murmured, looking at the blood staining her knife. "Let's go back. Quickly, now." He started walking home.

Xin started following him. She ran to catch up with him. When she reached him, she stopped him. She whispered. "Sorry for doing this. It was so that you could be happy." She walked on ahead, with Zap still standing there, where she stopped him.

(Yeah, I changed the wording up a bit, but it makes it all the more interesting! So tell me, which one was more interesting? Zap killing for Xin, or Xin killing for Zap?)

(I know that this was so not what I wrote in my comment, but you know that creativity is my specialty! That's how I went from Zap + Xin shorts all the way to Zap + Xin: TLF, anyway!)