Nurses in protective suits overpower a delirious man, who staggers through a hospital ward, banging into walls.
Trainers are using survivors of the Ebola virus to give frighteningly realistic courses to medical staff fighting the disease in Liberia.
The World Health Organization has constructed a mock Ebola Treatment Unit (ETU) in the capital Monrovia where doctors, nurses and medical students, some sent by the African Union, are being drilled in how to treat and deal with the dangers of the disease.
Doctors Without Borders (MSF), the medical charity that has been at the forefront of the fight against the epidemic, has been insisting that training health workers is key. Trainers constantly drum into the students that a treatment unit is useless if it lacks competent staff -- which is the case almost everywhere.
"We tell the health workers that our role here is to protect and save lives," said Shevan Jacob, one of the WHO trainers who worked on previous Ebola outbreaks in Uganda and the DR Congo.
Training takes two weeks -- three days of theory classes, then two days in a mock ETU before working for five days in a real unit under the beady eye of a mentor.
After the students get their certificate they are plunged into the horror of the real ETUs, where mortality rates can reach 60 to 70 percent.
"Many are afraid, they all have lost colleagues to the disease," said Jacob.
Liberia is the worst hit of the three countries most affected by the disease, with an official death toll of 2,069, according to the latest WHO figures released on October 1.
West Africa's nurses and doctors had never been confronted with the virus before the latest outbreak and so did not know how to protect themselves. They have paid dearly with their lives, with more than 200 dying across the three countries, whose already shaky health systems collapsed under the strain of the epidemic.
- 'Something needs to be done' -
In the "red zone" of the mock unit, where the sickest patients are treated, a woman sprawls groaning on a filthy mattress. The six survivors of the disease who are taking part in the programme bring a shocking realism to proceedings.
Jacob explains the scenario. "It's a woman of 24 who has been vomiting and who has diarrhoea, which has been getting worse over the past 24 hours. There is no bed for her in a medical unit. So we have to find a way to treat her in the meantime."
The carers, pouring with sweat inside their protective suits dripping with disinfectant, try to calm her.
She begs for water then "vomits" all the water she was given.
Ebola passes through body fluids -- so vomit cannot be simply wiped up. Instead a health worker must slowly and methodically douse it with disinfectant.
"And now what do you give her?" Jacob asks the students. "An intravenous drip," says doctor Nuah, his voice muffled by the protective mask which hides his face. Like his colleagues, his name and his job is written on his protective suit in red marker pen.
And so the training section called "managing a sick patient when a unit is full" gives way to the part on dealing with a "confirmed case". Then the volunteers move on to how to cope with a patient who is so confused he is banging into walls, and who goes into convulsions after nurses put him down on a bed.
"I decided to be part of this training because it's something that needed to be done," said Kobah, one of the fake patients taking part in the role play.
"We need to improve the ETUs," she added. The units are often overcrowded and under-equipped, short of personnel and do not reach the standards of hygiene and security necessary to beat the disease. Some are no more than places to die.
A medical assistant herself, Kobah knows exactly what she is talking about. "I had Ebola in August. They took me into an ETU on August 6 and I was discharged on August 28. I want to help train the people who will save Liberia."
The WHO hopes to train 400 health workers in eight or 10 weeks under the programme. Experts estimate that Liberia needs several thousand to defeat the disease.