Curtis mentions that after doing some research he figured out that despite all the crime that has been depicted in the show, they live in the second most dangerous place in America. This is a very subtle Batman reference, as there has always been jokes made in both DC shows and comics that Gotham City has the highest crime-rate in America, there is even a quote in Smallville (2001) where someone says "Do you know that Star City has the second highest crime rate in America? Well, if you count Gotham"
This is the fourth penultimate episode to be named after a Bruce Springsteen song; the others being "Darkness on the Edge of Town" (Season 1), "Streets of Fire" (Season 2) and "This Is Your Sword" (Season 3).
Diggle references other CW Show "The 100" when he mentions "Mount Weather" a location built to sustain a nuclear war
The underground Hive community is called Tevat Noah. This is actually Hebrew for "Noah's Ark".
This is the first episode in the show's 4 seasons to drop below 2 million viewers.