As for the lab, C-Alpha I recall I used it once before while infected by D-Bug (not sure of correct name) and it was not removed then. However, the decon room I have confirmed removes the 'unknown' dna source (Venus). Difficult to actually get to though...
I tried intentional modifications to both possible lab starts, ultimately both missed the mark in granting access to decon chamber in some way. After careful evaluation of everything and hints you have provided, I realized there was one other way I had already discovered brought me into the decon room other than the two main lab starts, that way was the only way that worked with me being infected with the Venus.
Now with Jessica, based on what you just described I have something to report that does not align (functioning not as described). It seems to be rng-like that I’ve been experiencing a larger number of cycles where I never pass any mirrors but Long after accessing Jessica’s room the transformation persists. One occasion I had walked around in circles for half an hour before getting tired of waiting. That was with a solid red-eyed variant, and it happens like that with a high lvl of consistency to me, so I’ve started just resetting when I roll one.