The first bomb, rigged to the flat’s toilet, has two triggers: a landmine-style pressure plate and the hallway light switch – cue McClure’s character almost detonating the device when she goes to turn the lights on.

“It’s pretty Hollywood,” says Gustafson. “But not impossible. The knowledge to do that wouldn’t come from the kind of information you’d find online. That’s coming from experience in Afghanistan, or someone trained by the Iranians in Yemen or something like that.”

Lucy Lewis is former EOD (Explosive Ordnance Disposal) and was Britain’s first female bomb disposal officer. She explains that bombs using two triggers are actually “basic”, and praises the show for eschewing fanciful tropes. “I was delighted that they didn’t do the digital-clock-counting-down-to-detonation business,” she says. “And no discussion about cutting the red wire and the blue wire!”

But Lewis says that a rookie mistake like flipping the light switch was a “spitting out tea moment”. Panicked, McClure’s character has to hold her finger steady on the switch while her partner deactivates the trigger.

“Every soldier across the land will spit their tea out at that,” says Lewis, who now works as Cambridge University’s marshal – the head of the university’s private police force. “On day one you’re told to never touch anything. If she’s done even a week at bomb school, she’d know never to do that.”

A real Expo would be less panicked, too. “You take a deep breath, compose yourself, and carry on,” says Lewis. “If you’ve served in Afghanistan, this is everyday bread-and-butter stuff. If you tread on a landmine you freeze. We practice it so many times.”

While the show’s two Expos tackle the device together, real bomb disposal officers go in solo. They take what’s called “the long walk” – a lonely journey to the live bomb. “Whatever needs to be done, they do it alone,” says Lewis. “Because it’s only one life at risk. They’d have a camera and people back in the van would be watching.”

Lewis appreciates the show’s small, personal touches, such as Lester’s character having marriage problems. 

“They all say EOD stands for ‘everyone divorced,’” laughs Lewis. “We said it would be a gross representation of the trade if they didn’t have marital difficulties in there. It’s a tight pressure thing. You have to focus, you can become very detached, and you try not to look at a photo of your wife and kids before you go on that long walk. That doesn’t help your mental state.”