BERLIN — Caught up in a melee of drunken revelers outside the Cologne train station on New Year’s Eve, Caitlin Duncan, a neuroscience student from Seattle, was terrified. She had somehow gotten separated from her German boyfriend, who had both their cellphones and her wallet. Ms. Duncan, 27, said that she was quickly surrounded and groped by several young men: One snatched her hat from her head, another tried to kiss her face and neck.

Like many of the hundreds of women who later said they had been assaulted in the crowd, Ms. Duncan sought help from the police, but said the officers were too busy trying to clear the square. But unlike other victims, whose complaints of attacks by foreigners of North African and Arab descent have ignited new debate about Germany’s ability to absorb migrants, Ms. Duncan said she was rescued by a group of Syrian asylum seekers.

Amid the swirl of criminal chaos, it seems, there were also acts of chivalry.

As the crowd swelled and grew more unruly, Ms. Duncan said, a stranger came up and asked if she needed help. Both of them spoke broken German, so the stranger summoned a friend who spoke English. He was Hesham Ahmad Mohammad, from Aleppo, Syria, who had met up in Cologne for the holiday with six or seven other Syrian refugees scattered around Germany.

The men offered Ms. Duncan money for a taxi to her boyfriend’s parents’ home: “the only address I knew,” she said. They would happily have called her boyfriend, Sebastian Samer, but Ms. Duncan had relied on speed-dial and could not remember the number. “I know there’s a lot of 7s,” she thought, “but that’s not helping me right now.”