BEIRUT, Lebanon — He had long been one of the more optimistic anti-government residents of the besieged, rebel-held section of Aleppo, trying to buoy others’ spirits even as loyalist forces closed in. But as the Syrian Army and allied militias took more and more territory in an apparently decisive offensive during the week, Yasser Hmeish, an accountant for the local medical council, grew frantic.

Soldiers seized his neighborhood on Wednesday while he worked at a clinic blocks away. Several of Mr. Hmeish’s neighbors were brought into the clinic wounded, but died before he could ask what had happened to his family.

“I don’t know anything, anything about them,” Mr. Hmeish said in an audio message, in one of scores of exchanges we had with people inside east Aleppo as the offensive unfolded. “We are about to die or be arrested.”

After years of bombing and months under siege, rebels had lost more than three-quarters of their territory in eastern Aleppo by the end of the week, throwing thousands of civilians and fighters into chaos. We followed the events in real time from Beirut, monitoring social media and talking via WhatsApp, Skype, telephone and other media with doctors, fighters, housewives, local council members, antigovernment activists, aid workers and others, including on the government side. All were people we had gotten to know through years of covering Syria’s bloody civil war.