Channel Seven details Sydney siege day

Channel Seven has kicked off its coverage of Sydney's fatal Lindt cafe siege by asking survivors to remember the lead-up to the terror ordeal.

After showing new footage from cameramen who realised something was wrong in the Sydney cafe, interviewer Melissa Doyle prompted survivors including Marcia Mikhael to remember gunman Man Haron Monis' face.

"Can I ever not see his face? And the answer is no," Ms Mikhael said.

The documentary then details what happened for some of the 18 hostages and what led them to the Lindt cafe in Martin Place on the morning of December 15 - whether it was a treat, a catch-up with friends, or work.

Hostages including Ms Mikhael, 82-year-old former tennis champ John O'Brien, Lindt Chocolate Cafe worker Elly Chen, 22, and software engineer Viswakanth Ankireddy, 32, are just some of the people on the special, which is airing at the same time as Nine Network's coverage.

The documentary revealed two of the women hostages were pregnant, two were mothers of three children, including the late Katrina Dawson, eight were Lindt staff, including shop manager Tori Johnson who was shot dead, four were Westpac employees, and one was an elderly mother with her daughter who has multiple sclerosis.

Mr O'Brien said once the doors to the cafe had been locked and they were trapped inside Monis was "ranting and raving" about Prime Minister Tony Abbott

"(He said) because Tony Abbott wouldn't come to the phone ... 'Tony Abbott will have all your blood on his hands when I kill you one by one'."

The documentary showed how Channel Seven was evacuated and Ms Mikhael remembers seeing Martin Place transform from a bustling thoroughfare to chillingly empty.

She remembers Monis saying he had two bombs.

Ms Mikhael also recalls how Monis wanted to know personal details about them, as well as checking if they were hungry or thirsty.

"He chose one of the workers to basically look after us. To give us water ... sandwiches," Ms Mikhael says, adding that Monis called her by her first name.

"We were calling him 'brother' because he was referring to the other two men who supposedly had bombs in the city as brothers."

It's reportedly one of the key reasons people didn't take a shot at Monis, because of the bomb threat.

s Mikhael and Mr O'Brien are the main interviewees in Channel Seven's coverage, with Ms Mikhael reportedly paid more than $300,000 for her story Mr O'Brien, 82 said to have received $100,000.

Ms Mikhael recalls the moment she realised Monis knew he would never get out alive, when she flat out asked him how he thought this would end up.

"'Don't worry I have a plan for myself'," she remembers him saying.

"I knew he didn't want to get out of there alive and because of that, I was very scared about how it was going to end."

Mr O'Brien, who was the first hostage to escape says he began trying to think of ways to hit Monis over the head with something.

But he says the hostages were separated.

"He had everyone in certain spots."

Mr O'Brien said he came up with another plan.

"I said 'look I'm having chest pains, is it possible to get a doctor in here' ... which I wasn't. He didn't fall for that."

It was when Mr O'Brien asked to go to the toilet that he saw an escape possibility - the green exit button on the door. He later fled through that door with lawyer Stefan Balafoutis.

Ms Chen became exhausted and panicked as the day wore on.

She pleaded with Monis to let her rest as footage showed the young woman nearly crumbling to the ground.

"He allowed me to sit down in front of him and he had the gun to my back I felt really scared because if I did anything wrong I would be the first one gone," she said.

It was Ms Mikhael who tried to calm down Ms Chen, telling her to think of happy memories.

"You're too young to die. You'll live. You'll be able to get out of here," Ms Chen remembers Ms Mikhael saying.

But because Ms Mikhael wanted to help, she left her safe spot by the door.

It allowed Ms Chen to crawl away under a table, where she met fellow cafe worker Bae Jie-un for the first time and they began planning their escape.

"Thank you from the bottom of my heart," Ms Chen said to Ms Mikhael, adding "she saved my life".

When Ms Mikhael was told the message, she teared up.

"I'm very happy that I was actually able to help ... if that's the reason I was there to help one person cope and one person stay alive, (that is more important) than I'm alive," she said.