He wasnt really throwing the match, he was clearly having his fun with yang
since when does semblance lower aura.....It only uses it, doesnt lower it
He lowered her to the lowest possible point, pretty risky. And Mercury couldnt have known yang would survive his barrage
When was it said semblance lowers aura...
I dont even get what your saying on that last point, but theres no point in framing Yang specifically, Framing coco or yatsuhashi would have been sufficient, yet they got their asses kicked, an Cinder didnt even rig the matches in this one for what we can tell, His surprised faces and gestures clearly made Mercury seem surprised, he even tried to defend himself by throwing a few kicks that yang dodged. He would have done that if he was trying to lose as yang was dangerously low.
None of that really says anything, backup plans can still be thoughtout and planned, and be praised. Emerald did what she did to attract to grimm and thats all that really matters
Theres things that also point towards him being surprise, such as his surprised facial expressions and a "holding-back move".
How to Hold back.
Seriously, theres no way mercury could have known she would survive that. He held back at the start but he clearly got serious.