I got the impression from what I read that there were two agents assigned to watch that roof from a conference room on the second floor in the building next door. They had an excellent view of the roof from the pictures I have seen. Apparently they were too busy playing Yahtzee on their phones or surfing for child porn, or whatever secret service “agents” do when they are “on guard”. The same rigor and attentiveness we expect from the people who were “guarding” Epstein in the New York detention center.
It was the conference room borrowed by the Secret Service to hold their pre-mission breifing.