People protesting against the stay-at-home orders in Colorado were confronted by a man and woman dressed in medical uniforms – apparently issuing a silent rebuke to participants.
Photos of the pair grabbed headlines and were widely shared.
Now the photojournalist behind the images tells the BBC what happened that day when "two worlds collided".
Meanwhile, some states are reopening businesses despite warnings from health experts that infections may spread.
Protestors agitating against state wide shutdown orders gathered in Arizona, Washington, Montana and Colorado over the weekend, trailing earlier gatherings in half a dozen US states.
Freelance photojournalist Alyson McClaran planned to capture Denver's protest, where hundreds of people had descended upon the state capitol building to demand an economic reopening.
Protesters in cars honked their horns and clogged streets, while roughly 200 people assembled on the lawn, brandishing signs and American flags.
"There were a lot of people there not wearing masks, not social distancing," Ms McClaran said of the "overly crowded" protests. "So I decided to leave and capture another part of the city."
Walking through the city's Capitol Hill neighbourhood, Ms McClaran spotted two people dressed in hospital scrubs standing in the middle of the street, preventing cars from moving.
"I literally just took off running towards them because I knew this was huge. I basically kind of blacked out a little bit because I knew this was so big," she said. "I just started firing away with my camera trying to get as much documentation as I could."
They "stood their ground", Ms McClaran said, even as some demonstrators shouted and hurled racist comments at the pair.
"It was honestly heartbreaking to see," she said. "It just felt like it was two worlds colliding."
Who are the protesters?
Those protesting say that the strict measures restricting movement and businesses are an overreaction to Covid-19 and unnecessarily hurt citizens.
Christian Yingling, a former commanding officer of the Pennsylvania Light Foot militia, called the protest "an acceptable risk".
"I'm gonna do what I got to do to feed my family," he said. "If it means I got to risk my health then so be it… and yes even potentially the health of others.
"My mortgage payments are late, my truck payment is late and if I lose either of those I'm dead in the water."
When you're quarantining healthy people, that's tyranny, he added.
"Our constitutional rights are getting viciously trampled right now. And people aren't going to put up with that for long."
But as confirmed cases in the US top 788,000 and the death toll rises above 42,000, public health experts and many state leaders have urged for continued social distancing to help minimise the virus spread.