The 22-year old citizen journalist and savior of the volunteer group White Helmets snapped photos of a leveled potato chip factory in Khan Sheikhoun on Friday while his friends and colleagues were cleaning the flames.
Suddenly a new explosion hit. This time Diab became a victim, but he kept his camera rolling.
The dramatic images that the White Helmets have given to CNN show that Diab is heavily bleeding, unable to stand, screaming for help.
"Boys, boys, please come with me", he calls to his co-workers, the video shows. "I can not move."
Several other men try to bring him to safety, but without a stretcher they are forced to drag him out, while his bloody legs walk through the dusty debris.
"I know you, I know you! My dear Anas!" says one of Diab's friends as he hurries to help him.
Then the whoosh comes from an airplane, another bomb lands and the men are pinned to the ground. One seizes his radio and asks for a back-up.
For more than two years, Syrian troops and their allies have washed out their enemies from parts of the territory that they recovered in the long-running conflict. Many of the opposition fighters and their families were attacked on Idlib, beaten by air raids in recent days in a regime operation to recapture the last remaining great rebel stronghold of Syria.
Up to 3 million people are packed in a rural enclave in the province of Idlib that borders Turkey in the north. Among them are about 70,000 fighters, their loyalty ranging from moderate to radical.
The large number of civilians who had been crammed into this enclave and the obvious disproportionate firepower used on them led the United Nations to warn that the operation would soon cause a "massacre". would become. US officials are concerned that the regime could use chemical warfare again.
Russia, the most muscular ally of the Syrian regime, has provided much of the air force behind Assad's territorial achievements in recent years. Russia and Syria say that they only target terrorists, an allegation contradicted by the accounts on the spot.
Amateur video that can not be independently verified by CNN shows scenes of chaos and slaughter in the province: families with children run through the shells of their homes; a woman who was piling under the rubble, except an excellent hand, still in motion; and bomb attacks, one after the other dark gray of the skyline.
Diab is one of the lucky ones; he survived and continues to recover in a hospital.
"They target innocent civilians and try to kill as many of us as possible," he said from his bed. "When I was rescued, I told the boys to hold on to the camera because it has material that can tax this criminal and send it to an international court."
Despite the risks, some citizens are taking to the streets in demonstrations that recall the early days of the Revolution against Assad during the Arab Spring of 2011.
Thousands of crowded squares in Idlib on Friday, activists told CNN, not calling for lofty ideals but for the right to survive.
"Idlib, we are dead with you", they sang, video shows.
They are perhaps the last words of this revolt.