Buck's is a bar above the Playground, used as a secret entrance and exit for the base.
Waiting for Talbot
In 2016, Phil Coulson waited at Buck's with a newspaper while WHiH World News was covering the Sokovia Accords Controversy, mentioning the Avengers Civil War, the Clash of the Avengers, and Steve Rogers being missing. As he looked the paper over, he read the obituary for Peggy Carter.
Coulson talked to Melinda May about the recent events to which May said that they did not have time to deal with the Sokovia Accords as they needed to stop Hive once for all. Coulson responded that he was going to meet with Talbot so as to handle the situation and explain to him what was going on with S.H.I.E.L.D. lately.
Glenn Talbot arrived and explained to Coulson that the President wanted S.H.I.E.L.D. to register every Inhuman they had by registering them as per the Accords. Coulson replied that he was not going to do that and instead took Talbot to a tour around the Playground.