With sensitive devices they listen for any response. Everyone is frozen in anticipation.
And then, a breakthrough. "Irem, my dear, I am close to you, you hear me, yes?" Mustafa says.
Those of us watching can't hear it, but it is clear now that she is responding. A small group of the girls' friends wait silently with us.
"You are superb! Now you stay calm and answer me. Ah ok, that's Merve. Merve dear, just answer my questions," he says.
Merve, 24, and her sister Irem, 19, were trapped under the rubble of their five-storey apartment block in Antakya, southern Turkey, which was flattened by the earthquake. It had been two days, but for them those days felt like weeks.
"It's Wednesday. No! You weren't trapped for 14 days. Give us five minutes. You will be out."
Mustafa knows it will take hours, but tells us: "If they lose their hope they might not survive."
Rescuers can hear Merve and Irem who have been trapped for days under the rubble of their apartment block
Merve and Irem start to joke and laugh together. I can see a big smile on Mustafa's face: "If they had space they would probably dance," he says.
By the rescuers' calculations it is 2m (6.6 ft) to reach the sisters but Hasan Binay, the rescue team's commander, says digging a tunnel into the concrete is a very delicate operation. One wrong move could lead to a catastrophe.
A bulldozer is called to very slightly lift and hold the thick concrete to stop the building collapsing when they start digging.
"Girls, soon we will give you blankets." Mustafa tells the sisters. "Ah no, you don't worry about us. We are not tired or cold."
Mustafa says Merve is worried about the rescuers' situation. It is 20:30 local time and it is very cold. This area has had one of the coldest winters that people can remember.
The rescuers start furiously digging and throwing the rubble away with their bare hands.But after a couple of hours we feel the ground suddenly shaking under our feet. It is a strong aftershock. Operations must stop and we leave the devastated building.
"There is a brutal reality here. The safety of our team comes first," Hasan says.
After 30 minutes, Mustafa and three other rescuers go back to where they were digging.
"Don't be scared. Believe me we won't leave you here. I will bring you out and you will take us for a good lunch," Mustafa shouts. The girls thought they had been left to die.
Merve after being brought out the rubble asked: "Am I really alive?"
It is midnight now and the digging has resumed. The team have hardly slept for days. We have gathered around a small fire next to the building.
Every so often there is a shout: "sessizlik", meaning silence. The light goes off, total darkness now. They have made a small hole in the concrete to see if the girls can see the light coming from Mustafa's torch.
"Merve! Irem! Do you see the light? OK! Perfect! Now I am sending a small camera down. Once you see it tell me and I will tell you what to do."
It is a moment of elation for everyone. Hasan joins his team to see the girls on the small screen connected to their night vision camera. They can see both Irem and Merve.
"You are so beautiful. Don't move too much. Irem pull the camera so we can see Merve better."
On the screen, we see that Irem is smiling. Luckily there is enough space for them between the concrete trapping them.
Relief floods everyone's faces. The girls look well and at least Irem has room to pull herself out if they make the hole bigger.
But almost immediately the team look concerned. Merve has told them that she has started to feel cold and there is something heavy on her feet.
The medics were worried: "Do Merve's feet have gangrene? Or is this the first symptom of hypothermia?"
It is around 05:00 now. The tunnel is big enough for the slimmest team member to crawl down. The rescuer was able to reach and hold Irem's hand for a few moments.
"Our mother's body has started to stink and we can't breathe properly," Irem tells the rescuers. The girls have been lying next to their dead mother for days.
Rescuers used a camera to see the women under the rubble
It is shocking. How awful that there can be moments in life when you would not want your mother next to you, we reflected.
Hasan asks one of Merve's friends - still waiting, stressed and silent - to show them the picture she has of the girls. They are trying to estimate the width they need to make the hole. The two girls are smiling, in party dresses, celebrating a wedding.
"Perfect! We can bring them out." The medical team gets ready with thermal blankets and stretchers. Everyone is excited. It is 06:30 and Irem comes first. She is laughing and crying at the same time.
"God bless you. Please bring Merve out too. Please," she begs the rescuers. "Merve will follow. I promise," Hasan tells her.
But bringing Merve out takes another tense 30 minutes. They need to free her feet from under the concrete without doing her harm. The operation is successful.
Once Merve is out, everyone starts clapping and cheering. I hear Merve screaming in pain but then asking: "Am I really alive?"
"You are dear," Mustafa replies, smiling.
The friends who have been here all night start shouting in tears. "Merve! Irem! We are here. Don't be scared." The sisters were loaded into ambulances and transferred to a field hospital.
After this joyful moment comes a chilling one. The rescuers ask everyone to be silent again. This is the last call.
"If anyone hears me, respond. If you can't respond, try to touch the ground."
Hasan repeats, imploringly, from different angles. Then sadly, with red spray he signs on the concrete, writing codes so other rescue teams will not search the building.
"Rescuing a human being is a beautiful feeling, but we wish there were no deaths." I can see the sadness in his face.
"Will you eat lunch with Merve and Irem?" I ask. He smiles: "I hope one day we can. But the most important thing is that they are alive and in good hands now."