The tank-shelling and gunfire started shortly after sunset, writes Channel 4 News Foreign Correspondent Jonathan Miller.
Major Adil, a brigade commander with the Jordanian Army border guards, was giving us the lie of the land from his desolate, wind-whipped army outpost, on a desert knoll, 500 metres from the Syrian frontier.
But bleak and uninviting as it seemed, Katiba Jaber base could never be described as "God-forsaken" - despite our first impressions. By the time the night was out, the cheerless, lonely hilltop would be resounding to the tearful exclamations of 149 muddy, exhausted Syrians - "Hamdulillah"... "Thank you, God!"
The major was just explaining that, from this command post, his men controlled three secret crossing points along Jordan's 387km-long border with its war-wracked northern neighbour. As he motioned towards one of these, down in the blackness below, the first shell streaked low across the horizon right in front of us. "They're firing at the refugees," he said. A flash, then... crump. And then another.
The gunfire started up. It was alarmingly close-by; but it took a moment to realise it was actually aimed at us. Bullets whistled low over our heads. The Jordanian soldiers broke into a run and hustled us behind some freshly bulldozed earth berms, then down, to their barracks - a right-angle of white shipping containers. Body armour, helmets: on.
"They shoot at us a lot," said the major. "That's why we had to build the berms."
"Do you fire back?"
"No. This is not our job," he said. "Our duty is to rescue refugees. They also shoot the refugees."
"Really? What, on this side?"
"Every night. Sometimes the refugees are shot."
If the Syrian Army's intention was to kill the refugees in order to prevent them from telling the world of the unspeakable cruelty they'd suffered at the hands of their armed forces, you could almost understand the logic. But that's not what it's about. It just seems that after 22 months of ever-escalating violence, Bashar al-Assad's soldiers - brutalised and brimming with sectarian hatred - have simply dehumanised their victims.
They shoot them down like dogs and leave their bodies to rot in the streets.
Later on Wednesday night, I would hear harrowing accounts of this depravity. Accounts delivered matter-of-factly from the mouths of children, as their mothers watched and wept.
Major Adil's men were in radio contact with the rebel Free Syrian Army commanders who shepherd the escaping refugees through the hazards along a frontier bristling with Syrian armour. Just before it got dark, we'd seen one of these tanks prowling along a road between government positions, not much more than a stone's throw from the base. At 8pm, I climbed Katiba Jaber's observation tower, which presented a three-storey target for the Syrians below.
A night-vision scope was bolted onto the roof, and in the tiny room underneath, Lieutenant Nawaf was directing proceedings. "Down, down, down; right 300..." I squeezed in to the airless room. A small gas fire was roaring at the lieutenant's feet. He was staring at a screen, the size of a small TV, on which the drama playing out in the darkness 500m from where we sat could be watched as though it was a movie.
"This tank. It has just fired," said the lieutenant.
"Here," he said. "He is hiding."
And there, plain as daylight, sat a Russian-built T-72 tank, partly obscured by olive trees. Another lurked close by.
"And here is what he is firing at." The scope-operator scrolled across to the left. "In this ditch there are more than 80 refugees. And here; this is the FSA commander. This is the most dangerous time," he said.
I made out the rebel commander before I could see the refugees. He was crouching next to a small mound, presumably out of sight of the tanks. After a couple of minutes, the refugees began to stand up; first just one or two; then the entire screen filled with a line of little black silhouettes.
Adults, children, some stooped and crouching, some carrying burdens on their heads; others laden with bags and babies. All, fearfully scuttling forwards in the blackness.
"They're coming now. Yalla, yalla, let's go," said Lieutenant Nawaf.
With a group of Jordanian soldiers, we headed down the hill. The moon had gone behind clouds; we stumbled over rocks, radios crackling as the FSA commander on the other side announced a change of plan. The gun and shellfire now made the intended route too risky. This was now Plan B.
The frontier, when we reached it, was a muddy ditch, backed by rolls of razor wire. Four rebel soldiers, heads swathed in red-and-white kaffiyeh, were digging at the banks. They were trying to build a bridge across the deep and treacherous mud to allow the escapees to quickly cross to safety.
I heard their voices first. Urgent whispers. A baby crying. Crouching down, I could see heads and shoulders against the night sky. There were so many; easily more than a hundred, I reckoned. Behind them, in the distance, a building, hit by shellfire, blazed orange.
Operation Mud Bridge took less than 10 minutes. This place was out of sight of the nearest tank position; the refugees used our camera light to pick their way across. You could see their breath in the crisp night air. I watched old ladies, clad in black abayas mumbling prayers, fumbling beads, take the hands of waiting Jordanian troops, who pulled them up the bank.
A mother, in a crimson coat, tears streaming down her face, four under-10s in tow. Another young woman with a newborn; a father, toddler on one arm, his family's possessions stacked on his other shoulder. There were old men who could barely walk and young men - probably FSA, but passing as civilians - there to oversee this exodus.
The trudge up the hill to Katiba Jaber was as much as these people could take after hours of walking, then hiding in ditches, stressed and braced for instant death. Grannies groaned with the exertion; family groups - three generations - trudging onwards, upwards in the darkness, eyes fixed straight ahead. It was distressing to witness so many people at the limit of endurance.
And then, suddenly, the "Hamdulillah" chorus started. We'd reached the camp. There were lights; gas fires, cold water, food, shelter and a dawning realisation that the terror of their flight into exile was now behind them. And that the terror of life in Bashar al-Assad's Syria was behind them too.
As they recovered from their journey and completed registration before their bus trip to Za'atari refugee camp, I sat and listened to the stories which came fast and furious from people who needed to talk about what they'd been through.
Not all talked. Some squatted silently, head-in-hands, rocking on the heels. Some wept quietly. Perhaps it was relief; perhaps it was for those they'd left behind. But there was a hamdulillah hubbub in that reception tent.
It was the sound of survival.
"Tonight we died many deaths," a woman called Fawzi told me. She said the refugees were repeatedly shot at and that five tank shells had been fired at them as they fled. Remarkably, we don't think anyone was shot.
A mother called Marwa - the one in the red coat, whom I recognised from the ditch - told of the heartless violence meted out on her family by soldiers of the regime.
"We begged him not to burn our house down," she said. "Hamad, my son, even grabbed his leg and called him 'Uncle' and pleaded with him. But he called me a bitch and said if I didn't leave the house, he'd burn us in it." What traumatised her most was what her children had been forced to witness.
Ten-year-old Hamad, she said, had seen severed heads and bodies littering the street of his home village, Bosra al-Sham, near Dara'a. "One day they fired 200 shells at our village," said Marwa. "In the end, there was no electricity, no gas, no food, no water. We had no choice. We had to go."