Baghdad (CNN) Flanked by friends on a busy downtown Baghdad street, Asa'ad al-Yassiri pulls out a tattered piece of paper. It's his medical release from the Iraqi military, allowing him leave for a bullet wound to his left arm.

His contingent was among the last to withdraw from Ramadi after an ISIS offensive.

He's disillusioned about how they left the key city -- especially the mystery surrounding the order to withdraw and how ISIS prisoners earlier were spared from execution.

In the brutal, seesaw struggle for territory and power between ISIS and central governments in Damascus and Baghdad, Ramadi has become the latest battleground in Iraq.

Since the takeover of the city in Anbar Province earlier this month, close to 55,000 people have fled , the United Nations has said. Most of the displaced persons headed to Baghdad, about 120 kilometers (75 miles) to the east.

Bulldozers rigged with explosives

ISIS has proved to be dogged foe for the Iraqi military -- and that again was the case in the battle in which al-Yassiri found himself.

Al-Yassiri and his contingent were positioned just to the west of the city, in open terrain, using berms for cover. The men, about 140 in along this particular front, were split into smaller units of around two dozen.

ISIS, which calls itself the Islamic State, had targeted some of the positions on either side of al-Yassiri's unit and inside the city.

"There were three roadside bombs that took out two Humvees and killed five of us. Then they came at us with the bulldozers rigged with explosives," he says.

The firefight lasted for hours, its final moments captured on a cell phone video. One soldier fires back from behind a berm. Right next to him is a body, that of a comrade killed in battle.

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Chaos ensues as more gunfire erupts. Al-Yassiri's commander radios for air support shouting to his men "Fight, heroes, fight!"

The unit fires back.

Someone shouts a warning: "They are coming from the other side."

ISIS fighters were advancing on them from four directions. The unit that was supposed to be protecting their back seemed to have disappeared. They were vulnerable and exposed.

Someone screams for more ammunition. Al-Yassiri jumps out of an armored personnel carrier and runs to the soldier.

"The bullet hit my flak jacket at an angle and went into my arm." He fell to the ground. Another soldier dragged him to safety.

Moments later, another bleak cry of "no ammunition, no ammunition." It was followed by orders to withdraw.

Al-Yassiri says he had no choice but to obey.

"We had martyrs and wounded, but we said we won't withdraw, we are used to the blood of martyrs and we have not liberated the land," he said. "But then the convoy withdrew, so we had to withdraw as well."

Al-Yassiri: Blame lies with leadership, not soldiers

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Al-Yassiri is bitter, angry and disillusioned. Two weeks before the fall of Ramadi, he says his unit captured an ISIS position, killing six ISIS fighters. Two are seen torched in a video. Another seven were captured, among them four foreigners, admitting they were tortured for information.

"I heard my officer interrogating one of them how they manage to plant IEDs between our watchtowers when they are just 100 meters apart?

"One replied saying, 'We flash our light toward the tower. We know there are only 28 soldiers, that they are in five hours shift rotations and there is a lack of ammo. If a soldier doesn't fire at us, we crawl and plant the bomb.' "

"We wanted to kill those seven we captured," he continues. "But we couldn't because our commander had already informed our headquarters that they had been captured."

He bristles at the notion that Iraqi soldiers like him don't have the will to fight . He faults the military leadership and logistical failures that left them without adequate resupply and support.

He believes that the order to withdraw was a betrayal. The Iraqi government has said it launched an investigation to find out what went wrong and how the order was issued, but so far, no one has given a viable explanation.

"I want to quit the army, I would, if I thought I wouldn't get into trouble," Al-Yassiri says. "I want to join the militias and go back to the fight."