you have to visit kyrex at the gym before going back home to Diego and then when the main character asks if he should go through with it say yes and you will have the special scene with kyrex which is optional that is the special scenes that you missing the one with kyrex were you have sex with him hope this helps you!
Viewing post in Sileo: Tales of a New Dawn comments
This is correct. Put simply, do all 3 of Kyrex's side plots. These are only available for a couple of days, so if you do them as soon as they pop up, you'll be fine. You'll be given at least one opportunity to back out, make sure you don't. Doing this will result in a bad ending on Day 7, but you can restart the day from the bad ending screen which will reset your progress on the third side plot - just don't do it or back out of it to avoid the bad ending :)