The man (Mr. Samuels) who was fired by Natalie over the computer, but who was sitting in the room in front of her (and all of his co-workers, who were fired off-screen via the same method): wouldn't they have recognized the office behind Natalie as their own office, or, since we see Mr. Samuels walk by the glass wall separating Natalie from the office, wouldn't someone who was fired look inside and see the woman who fired them was in the room next to them, and get pissed off?
Good point. It was very worrisome when Samuels raised his voice and Natalie started looking at the room he was in, possibly about to erupt. But considering the fact that the guy had an emotional breakdown and couldn't even respond (how many times did Natalie say "Mr. Samuels"?), I think he was just too devastated to pay attention to subtle things like noise sources and faces in his peripheral vision. Sure, a calm and collected guy would have enough free time (mentally) to notice, but Mr. Samuel's brain is just too full of pain and anger to notice.
If Alex is only seeing Ryan as an escape doesn't she worry things are getting a bit serious when Ryan invites her to his sister's wedding?
She did say that she thought he knew it was just escapism. When they met, she told him that she was under the impression that they treated traveling similarly - that their travel lives were totally separate from their home lives.