Alright, this idea popped into my head. I edited this again so it's not so rushed.

In an open area at Mistral, near Haven Academy, there was a wide area within a building. It was a large area typically used as a space for celebration or, in this case, for fighting. The echos of punches and kicks with a few shots from their weapons resounded throughout this building as a blur of gold and silver seemed to dance together.

Mercury and Yang had been fighting for awhile. She was angry at him and fought him with fury but she still had to keep control of herself. She remembered fighting him: he was strategic and clever. She realized when Ruby told her about her encounter with him that he likely meant to let her win last time. She wasn't about to be fooled by him again. Mercury noticed that she had changed. She was more careful now and didn't afford to take any hits unlike last time where hitting her was just a bonus at the time for her because she relied so heavily on her semblance. Fighting her now suddenly became a lot more fun: she was actually using her brain. And Mercury originally thought she was just beautiful, blonde, and temperamental with all brawn and no brain. She had grown unpredictable and strategic, almost equaling him. But, he could still block and get some hits in. It was still not enough for her to use her semblance. Maybe he could get her to activate her semblance again. That was the real fun in fighting her last time and maybe she'd be even more of a challenge if he activated it.

"So, looks like you traded your arm for a brain." Mercury said.

Yang bit her lip, not to keep her temper in check but to keep herself from grinning. At this point, she can acknowledge that he's not wrong in someway. It did take losing her arm in order to learn how to fight like this after all. Mercury was surprised that didn't work.

"Yeah, I guess I did. What did you trade for your legs? Obviously not a bigger dick." Yang said with a smirk.

Oh that did it! Mercury never took well to insults, especially if it involved his legs. Yang was startled when he was the one to get angry. She grinned and blocked a kick.

"Hey, don't give out what you can't take, pal." She said, dodging another kick.

Mercury forced himself to calm down because, well, she was right and losing his temper could give her the upper hand now that she has gotten better. They then continued to fight seemingly endlessly. Mercury started getting the upper hand and decided to try and piss Yang off to activate her semblance. He dodged a punch and move passed her but, as he did so, he grabbed her butt. Yang was annoyed but not angry. She's gotten groped plenty of times while fighting.

"Really? What are you trying to do?" She asked, throwing another punch.

"What? I'm getting bored." He said, dodging another hit while smirking.

Yang rolled her eyes. He was trying to piss her off, she knew that much but she already knew why: they were essentially at a stalemate and activating her semblance could make or break this battle for one of them. They were evenly matched to the point that no one is really getting anywhere. But, until she sustains more damage, there was no way she was going to activate her semblance. He then tried again, groping her breast as he passed. Nope, still no reaction other than a slight blush and an annoyed look. So she decided to charge after him and try to throw as many punches as possible, hoping that maybe she could tire him out. So she turned back over to him and then they became a flurry of kicks, punches, and mostly blocks. They kept this up to the point that both of them started getting tired. Even their stamina seemed equal. Mercury was lying when he said he was bored: he was having the time of his life. This had to be one of the best fights he's had in awhile even if it took so long. But, Yang had an idea as they both parted to catch their breath. Since Mercury liked to cop a feel every now and then, maybe she could exploit his obvious attraction. It was worth a shot even if she might also get distracted and hit... but only if the opportunity comes up. Mercury wondered why she had stopped throwing punches even though her reason was the same as his.

"Well? Come at me, blondie." Mercury said, despite his heavy breathing.

Yang then grinned and leaned forward so that he had a good view of her cleavage. Her sudden change in demeanor didn't go unnoticed.

"If you're so eager, why don't you come over here, big guy?" She said with a flirtatious grin.

She was flirting with him? What is she planning? As fine as her breasts were, that wasn't going to distract him enough to warrant any weaknesses. Without saying another word, Mercury launched himself towards her. She then blocked his kicks and punches. He gains the upper hand and grabs both of her arms, thinking he has her subdued but she had him right where she wanted him. She could now try to see if he was weak to this.

"Hah! Try hitting me now-mm!" he began.

Yang had cut him off by placing her lips over his, an action that surprised the hell out of Mercury. His hand on her arm slackens and she tries punching him, only for him to block it but he didn't pull away. Two could play at this, he figured, melting into the kiss, pinning her against the wall. Yang was half way tempted to punch him again but his tongue in her mouth was very distracting. For a bad guy, he wasn't a bad kisser. Mercury acknowledged somewhere in the back of his mind that this would be the perfect opportunity to subdue her but the taste of her tongue was just too good for him to ignore. He put his arm around her waist and she put a hand on his shoulder. They both forgot that they were enemies for a moment. They parted soon and neither of them had any idea what to do now. He rested his forehead against hers and looked at her, scanning for something, trying to figure out why she just suddenly decided to make love instead of war.

"Well... that didn't go like I planned." Yang said.

He chuckled. She probably hoped it would have distracted him enough to get a hit in. The logical thing to do would be for one of them to subdue the other but right now, neither of them moved. Yang had just brought something out that should never have even been considered. She didn't know if she should hit him or hug him. Mercury then kissed her again, unable to resist the urge. He also wanted to see if it would cause them to resume fighting. Yang didn't fight him too much, opting to wait until he lets her go, enjoying this turn of events more than she should. She had a feeling that he wasn't going to hurt her anymore or at least for tonight. He would have done that already because she is currently very vulnerable. Finally, he relented and got off of her, backing away.

"Well... shit." He said.

"Aren't we supposed to be fighting?" Yang asked, still dazed, her hand on the wall to support herself.

Mercury leaned against a nearby pillar. They both stood in silence, Yang's cheeks flushed red.

"Just go... I'll tell them we cancelled each other out. I'm not in the mood to fight now." He said.

Yang looked at him, slightly surprised. But, it was better to be able to go off and help the others with some strength and aura left than none at all.

"It's a shame you're with them. I might have given you my number. Just don't expect me to go easy on you next time." Yang said with a wink.

She walked past him and he spanked her butt.

"I won't either but, if we're both alive after this, I'll take you up on that offer." Mercury said with his signature smirk.

She was about to leave the room but, before she did, she decided to say one more thing.

"In case you ever change your mind about fighting with them, we could always use more help." She said before walking away.

He watched her as she left. He suddenly realized what he did and he wasn't sure if he should regret it or... take her up on that offer.

I really could see Yang attempt to distract him with a kiss only for it to backfire like this. If you even call it backfiring.