With cupped palms, she pours it down her parched throat.
"I didn't know if it was rainwater or dirty water or what type of water," she later says. "It didn't matter."
She doesn't know it, but she's in the flooded basement of Rana Plaza.
It's 170 miles from Dinajpur to Dhaka, a trek along congested roads that can take up to 10 hours.
Reshma's mother heard of the collapse on TV. But there was no way for her to reach her daughter.
Reshma had sold her mobile phone three days earlier to help pay rent.
Scrounging up what little change she had lying around, Zubeida boarded a bus to the capital.
She checked the morgue and the hospitals.
She showed a picture of Reshma to every rescuer she met. No one had seen her.
For the first few days, she steadfastly held on to hope. Rescuers had been pulling out survivors from the rubble by the dozens each day. More than 2,000 of them in all.
But as the days passed, the number dwindled. And with it died Zubeida's hopes.
She wandered aimlessly around the disaster site.
Strangers brought her rice, offered her an umbrella, consoled her.
"I wanted my daughter's body," she said. "I wanted a leg or an arm or anything that I could take home and bury."
Three minutes without air. Three days without water. Three weeks without food.
That's the survival rule of thumb.
In Reshma's case, circumstances conspired to keep her alive:
The air that seeped into the crevices. The crackers she found. The water she drank.
The complete darkness may have helped too, doctors say.
Without knowing day from night, she couldn't keep track of time. She didn't know officials had determined there was little chance someone could survive past a week under that mountainous pile. She was unaware that the rescue mission had long given way to an operation to recover the dead.
And sometimes, the not knowing keeps one going.
"Allahu akbar. Allahu akbar."