He deals with terrorists for a living but for Shiraz Maher, contracting Covid-19 pneumonia was more scary than anything he has ever encountered.
The 38-year-old British academic, who is one of the country's most prominent government advisers on Islamic radicalisation, described his experience of the disease in a mammoth twitter thread.
"It's a completely mad, crazy illness," Maher said.
"It has made me feel more intensely ill than I've ever been in my life."
Maher said he had been vigilant about protecting himself from the coronavirus but, because he was relatively young with no underlying health conditions and a non-smoker, believed he could "shake it" if he caught it.
"Here's how things have played out. Firstly, it's not the flu. Whoever originally said that, did everyone a great disservice. This thing is not the flu. It's a nasty, horrible, illness," he said.
"I started having symptoms about two weeks ago. The fever was mild and went very quickly. Is it Covid-19? Who knows, but I've shaken it quickly. Great. Then my lungs started packing up and my chest got very tight. This happened around 15-16 March.
"The cough was dry and unlike anything I've ever had before. It was much more extreme and pronounced than a dry cough you might have during a bout of the flu. It feels like there's something deeply lodged within your lungs, that they're (violently) trying to eject.
"Of course, there's nothing to actually eject. The resulting cough is dusty, dry and painful. Much more scary is that you're unsure of when you'll stop coughing. You have no control over it. There were times I was worried I'd start vomiting because the coughing was so severe.
"When you finally stop, it's a relief — but now you're in a new phase altogether. You're fighting to draw air into your lungs but your chest is tight and, frankly, your lungs are in distress. They're not functioning the way they should.
"Your head is also pounding because of the violent coughing. I suffered terrible headaches after these coughing fits. The evening of Wednesday 18th was the worst day for me. I fought for breath for about 3-4 hours. It was horrific."
Mr Maher said he recorded his symptoms and ran them past his doctor friends, who told him he had: "Classic Covid".
Not wanting to further burden the British health system, which is already struggling to cope with the daily surge of coronavirus patients, he did what he could to manage his worsening symptoms at home. Struggling to breathe and stay awake, he went to bed for two days.
"By Friday, I thought I'd got through the worst of it and things were looking good," Maher said.
But he was blindsided when his condition suddenly took a turn for the worse and his blood pressure shot up to the point where he feared he would have a heart attack.
"Coronavirus is particularly cruel. Recovery is not linear," he said.
"On Saturday night I started to feel distinctly unwell again. I decided to take my blood pressure because I have a home monitor.
"Anything over 180/120 is classified as 'hypertensive crisis' (basically, heart attack/stroke territory). Without revealing what mine was, lets just say I was well, well in excess of this (again, I don't have an underlying issue). This was easily the most terrifying moment.
"I called my doctor friends and told them. 'Time to call 999' (the British equivalent of 111) they said — so I did. It took more than 15 minutes to speak with a representative; that's how overwhelmed the emergency services are. I told them my BP and that I have coronavirus.
"Ultimately they decided they couldn't respond to my call. I am not criticising the London ambulance service. They are doing superb work under incredible, unprecedented circumstances."
Over the next 48 hours, Maher remained in bed in a bid to bring his blood pressure down naturally. His hacking cough began to subside and his chest started to feel "less tight".
But just when he thought he was finally on the mend, Maher was hit by a raft of new symptoms, including "crazy abdominal pains and headaches" and extreme lethargy.
On March 28, two and a half weeks after the first signs of coronavirus appeared, Maher said he finally felt like he was "starting to beat it" and took to social media to share his horrific experience with others.
"Coronavirus appears to have a completely different trajectory in different people," he said.
"Some are shaking it off relatively easily. Others are suffering very badly. The most difficult part of this is the extent to which it takes hold within your lungs … It's a completely mad, crazy illness. It had made me feel more intensely ill than I've ever been in my life."
Disturbingly, because Maher was never hospitalised or put on a ventilator, his case has been classified as "mild" by British health authorities.
You can read the full thread below:
I've been debating about whether to 'go public' on having coronavirus - which I kind of did inadvertently this morning. So, now I may as well share my experience(s) with you in order to help those who are worried about it or who are thinking they might have it. Here goes... 1/