

It seems Lana and Daniel's secret is revealed now, or this is just a dream?
Now that you mention it, I was surprised to see Lana sleeping naked in the bed she shares with her husband when that way, he could catch a glimpse of any marks that Daniel might have made (voluntarily or involuntarily) on her during their great night of sex. Also, the beginning of that scene reminded me of that dream she had after finding out that the long vacation far away that she had planned with her husband had vanished because he had received an email from "his company" asking him to shorten it and to be nearby in case of any eventuality (if I remember correctly, it happens in ID6).
So, I think we're looking at another dream of hers. However, if we're looking at something that actually happens in the story, I think there would be some timely interruption to prevent Alex from seeing his wife cheating on him with their own son (in that image, it seems that he's focused on the door he's opening, not on the room, so it's possible that someone behind him (probably Sofia, because this way she would show Daniel and Lana how useful she is to both of them, trying to convince them to join her forbidden relationship) calls him and he ignores his intention to enter, allowing Daniel and Lana to avoid being discovered).