An hour’s ride on an ambulance, its siren wailing through near-empty streets dotted with checkpoints fortified with sandbags and armoured vehicles, brought a group of Indian medical students from their Dhaka campus to the airport.

These five students of the IBN Sina Medical College in Dhaka were among the hundred-odd Indians who flew into Calcutta from a turmoil-hit Bangladesh on Saturday.

They said the nervous ambulance ride and what they saw of the protests would remain etched in their memories for life.

Their flight was packed, mostly with Indian students and professionals returning home from various parts of Bangladesh after a nationwide curfew was imposed and the army called in to contain the clashes between anti-quota protesters and security forces.

Minhaz Ahmed, a third-year medical student from Guwahati, said he and his friends had managed to coax an ambulance driver they knew into taking them to Dhaka airport.

But before that, they needed air tickets. With the Internet down, that seemed impossible.

They frantically called their relatives in India to book tickets for them on "any flight available". But even the phone lines were often unreliable.

Eventually, the tickets were booked but with the Internet down, there was no way to send them over to the students. So, the families texted them their PNR numbers.

The group set off around 6am and arrived at the airport armed with the PNR numbers on their phones and prayers on their lips.

“We could only carry a backpack each, there was no space for any more luggage in the ambulance. We kept our passports and college identity cards handy,” Ahmed said.

Ahmed’s senior, Arsin Rizvi, who is from Moradabad in Uttar Pradesh, said the students had seen clashes between the protesters and the security forces on Thursday as well as Friday.

“Our campus is in Mirpur. We saw violent protests on the streets. The Mirpur-10 Metro station was on fire. During the ambulance ride, we saw the roads strewn with stones. There were smudges of what seemed a soot-like substance on the roads along with what looked like shells,” Rizvi said.

On Friday, Dhaka localities such as Mirpur, Rampur, Mohammedpur, Uttara, Jatrabari and Badda saw intense clashes between the security forces and protesters.

Wasif Imam, another student from the group, said they had been stopped “seven to eight times” by uniformed security personnel at checkpoints.

They were first stopped at a sandbag-buttressed checkpoint by men carrying rifles near the Agargaon Metro station, not far from the Liberation War Museum.

“The men wore helmets and bulletproof jackets. They stopped the ambulance, peered in, and ordered us out. Our hearts sank, we thought we would be detained,” Imam said.

But they were waved on after a thorough search of the vehicle and their bags.

“We told them we were Indian students headed to the airport,” Imam said.

Kalikapur resident Gairik Samanta, who was on an official trip to Dhaka and returned to Calcutta on Friday evening, said he had to set out from his rented accommodation at 5am although he had an afternoon flight.

“I started early as I thought a lot of flights might get rescheduled and wanted to reach the airport as early as possible,” he said.

“On the way, I saw the city pockmarked with scars of the clashes. I have been visiting Bangladesh for several years but never saw anything like this before.”