Thigh pulverization

We have this Paramount Leverage Squat machine, that is kind of a wicked machine. It usually just sits there, very uninviting. No one wants to even acknowledge its presence. It is not an easy machine, actually quite hard to get used to, hence its unpopularity. We have been using that. We did leg presses prior to them. I took a tight control on all of the down movements on the presses, slower than usual. I was imagining myself in an inverted squat. Back to some slow repping on extensions and curls, too. I love/hate that. ANyhoooo, what yesterday's session did to me -
I live on the third floor of a condominium building. I have to walk up / down four sets of nine stairs each. 36 total stairs. Short of a few times that I have been injured, this was the most tortuous trip down the stairs I have ever taken. My God!!! The mid outer thigh area is pulverized. Up was a test, but tolerable. But Down!! - I almost laid down and rolled the way down to alleviate the pain. Wow. I'm inclined to stay inside for the next few days just to avoid the trip back down. I'm not even sure if I have soreness in any of the other areas of my legs, this is so darned overwhelming. Broderick says my body likes being a bodybuilder. I say poppycock.