A police officer stands guard at South Station on April 19, 2013 in Boston, Mass. South Station was shut down and heavily guarded with police in response to the early morning shootings in Cambridge and Watertown. - 

Boston and its surrounding suburbs were on lockdown Friday morning as police searched for the remaining suspect in the Boston Marathon bombings earlier this week and authorities urged residents to remain in their homes.

Businesses in the area were also asked to remain closed, but there was at least one outlier. Athenahealth, Inc., is a cloud-based provider of electronic health records and care coordination services to medical groups and health systems based in Watertown, Mass. This morning, co-founder and CEO Jonathan Bush sent out this letter to employees and athenahealth's social media network, stating that the business would continue on.

"We are open for business. WIDE open," Bush wrote. "Though the exact motives of this attack are still unclear, the point of this kind of terrorism is to generate enough widespread fear and panic that a society freezes up and stops functioning."

"At athenahealth, we don’t allow that. We don’t flinch."

The lockdown was lifted around 3:09 p.m. PST.

In an interview with Marketplace early Friday, Bush said it was important not to allow terrorism to stop progress.

"It is the fundamental intention of terrorists to stop that momentum, and so if you've got a shot at leaning some extra momentum in, that's your cue. We've felt it that way, big time," he said.

Bush said besides two employees "far away from the glass, behind rows and rows of men with guns and some cameras" at the Watertown headquarters, the majority of his 2,339 employees were working in the cloud or out of the company's six offices outside of Boston. On a typical day, around 1,000 employees work from Watertown. 

"We've doubled down on the work that we have to do manually. Most of that is in our Belfast, Maine, location," he said. "The client support center's been up the whole time. And the guys who do [research and development] and new stuff, they can work on their laptops from anywhere ... so far everyone's just been banging away over email and chat."

"I supposed we're a little bit lucky as a cloud-based company, it's easier for us to activate and respond," Bush said. "But I think most of the people watching TV are thinking, 'What the hell can I do right now? I wish I could do something.'"

Bush said he was confident that with a bit of weekend work, there will be no backlog come Monday.

"We're proud of that, to keep that going for our clients, and for the principle of the thing."

Update: This story was updated at 3:09 p.m. to reflect that the lockdown in Boston had been listed.

Follow Kai Ryssdal at @kairyssdal