The Division files already had taken a thorough undertaking by a Redditor regarding 58 guns discovered during the beta test. Perhaps these tie into what was seen here?
Reddit user TheEmqeror also found some interesting information on the second installment of the DLC expansion for The Division Survival. He saw the description for the expansion and it translates into this.
"Expansion 2: 'Survival' - In this expansion the entire map transforms into a Dark Zone for a hardcore multiplayer experience."
"In the second expansion, called 'Survival', players will have to try to survive in a hostile environment that will challenge even the most hardcore Division players."
This isn't surprising as there seems to be a focus on The Dark Zone, as Forbes cited in their article last month as this is an area that "will make or break The Division," and with the aforementioned description of the second expansion, this could be the tie breaker. The author of the Forbes article stated the following.
"I almost wish the Dark Zone was its own game entirely, to be honest, with factions developing entirely organically, and groups of players banding together to hold entire sections of the city against other hostile groups."
Keep in mind, it was stated by TheEmqeror that this would not mean the current map will be transformed into a Dark Zone, but would be an option to play separately in a full Dark Zone area. If this is the case, this would make sense for it to be challenging and intense according to The Division's Survival DLC expansion.
The Division fan TheEmqeror even went as far as to confirm with chat support at Ubisoft if the overseas description correlates to each other. Ubisoft asked for information such as a screenshot from him/her to confirm. Sure enough, confirmation was made.
Other rumors made in the past about a raid scenario going on at Riker's Island that would entail an "eight player end-game raid," according to Express, as additions to the game, but didn't suggest it to be part of the scheduled expansions.
There are, however, according to a recent Year One plan, free updates called Incursions and then Conflicts in a recent report by Ubisoft. Perhaps this where the Riker's Island raid may lie in The Division?