JACKSONVILLE, Fla. -

From movie theaters to schools to military bases, there have been multiple mass shootings across the U.S. in recent years.

Many companies are trying to prepare for those scenarios as best as they can.

On Thursday, Nemours Children's Clinic had the Jacksonville Sheriff's Office at its building downtown trying to put a worst-case-scenario plan in place.

The clinic has 12 occupied floors and more than 200,000 square feet. If there was a gunman on the property, that could take authorities a long time to locate that person. That's why Nemours wanted to have SWAT there to work out some potential glitches in a plan before it's too late.

The plan to have JSO hold a mock shooter drill at Nemours has been in the works since early May, but in light of the shootings at the Navy Yard in Washington D.C. earlier this week, it made having a plan in place even more important.

"This is the world we live in now and this is the time to prepare for an incident like that," said Richard Michaux, facilities manager at the clinic. "This is something you hope never happens. This is the kind of place we want children and parents to feel safe coming to."

Michaux says that this is the first time Nemours has done something like this. He is hopeful that the employees who are able to take part in the drill see firsthand how the best way to respond would be if something like that happened. He also said this drill was good so that JSO knows the inside of the hospital in advance.

"It makes the outcome, although tragic, it will make the outcome a lot better if you do this to prepare rather than try to think about what you're going to do the day of an event," Michaux said.

"When you have everyone trained and on the same page, it can go much smoother rather than having people running here and there, bumping into each other, creating a more dangerous scene, Channel 4 safety expert Ken Jefferson said.

He said it's important for more companies to do drills like this. Given the recent shootings, people agree having a plan and a practice run every so often can help save lives and work out any glitches before it's too late.

"We want to make sure that we expose any of our gaffes or weaknesses we may have so we can close them before hopefully ever one of these things might happen," Michaux said.

Nemours put up signs saying it was holding an emergency exercise Thursday to let people know it was not an actual emergency.

Some patients said they were happy the clinic was being so proactive to avoid a tragedy here in Jacksonville.