Might Have Mogged My Interviewer - Any Advice?

Hi all,

I interviewed at a BB earlier this week for SA27, overall felt like things went really well at the time but there were a few things in the interview that might have gone wrong at the time looking back at it. 

I went through my TMAY and Why IB answers, and those went great. However, when my interviewer asked me for my answer to "Why this bank", I could definitely see a tone shift in the room. I go to the gym a lot, and my suits fit pretty tight so you can tell I am quite toned. I sat a bit straighter in my chair, exposing my muscular frame and making myself appear a little taller, even though we were both the same height. I didn't mean to do this, but I could tell he was reacting with a bit less emotion and didn't look as relaxed. He then asked me about a time I led a team, and I talked a bit about my fraternity to ease up the tension, but that didn't seem to liven up the mood.

He then asked me an easy technical, and a couple more after that. I could see a slight bead of sweat on his forehead, but I'm not sure why he was reacting that way. I was genuinely just trying to correct my posture - I didn't mean to appear like I was trying to one up him. The interview went by pretty quickly after that.

I stood up to shake his hand afterwards, when my next interviewer walked in at the same time. He quickly scurried out of the room and didn't make eye contact with me as he said his thanks. Was just notified by HR that I was placed on the waitlist, and this was the only round where I noticed anything that could have been improved. Did I height mog my interviewer by accident? Would really appreciate any advice to improve in my next superday.