When Korsak finds the binder of swatches, he puts it down on the bar with it closed. When the shot changes and Angela tells him what it is, the binder is suddenly open and Korsak starts flipping through it.
Prior to and during Korsak, Jane, and Maura being told to stay where they were, there were numerous other personnel seen walking around the area. None of them were told to stay where they were. Additionally, one of them or one of the other first responders such as the fire department would have triggered one of the other mines since they were shown walking in those areas.
In the title and throughout the program, the term bomb was used. A buried explosive with a pressure trigger is normally called a land mine, not a bomb.