We might just have to kill the hostages.
The Flag Smashers drag barricades in front of the NYPD Emergency Services vans, before forcibly removing the officers. Bucky joins the fight, and later John Walker and Sam show up to have various fights and discussions here.
The entire New York sequence with the Bucky and John Walker fighting the Flag Smashers takes place in Atlantic Station at the intersection of 17½ St NW and District Ave. Bucky makes his approach by Motorcycle on 17½ St from Atlantic Dr, while John Walker approaches from the East side of District Ave.
John Fighting Karli inside the scaffolding takes place on District Ave at the corner of 17½ St, in front of the Security and Safety office windows. When Bucky is helping an injured Sharon Carter, they are just East of District Ave, with the Subway Sandwich shop in the background.
(The Falcon and The Winter Soldier S01E06, 2021)