A security guard has pleaded Not Guilty to one charge of aggravated menacing Monday in his first court appearance since he pulled a gun on a Lucas County Sheriff's Deputy at a local IRS office.

That deputy is still trying to wrap his head around a potentially fatal situation that arose out of what should have been a simple encounter. The deputy came to 4 Seagate to ask a question at the IRS office. A step that nearly cost him his life.

As Lucas County Sheriff's deputy Alan Gaston enters the IRS office, he's in full uniform with his badge with his firearm visible.

He was on duty May 31st but says he stopped at the office for a phone number to ask about a letter he got from the IRS. Deputy Gaston says the guard told him he needed to put his gun in his car. Gaston said he couldn't do that. The conversation ends with a gun pointed at the deputy's back. Gaston vividly remembers "that" moment.

"Basically preparing myself to be shot at that moment. Bracing for a shot in my back," said Gaston.

The whole thing caught on security cameras, as the guard follows deputy Gaston to the elevator with the gun out and it appears his finger very close to the trigger. The guard then tries to take Gaston into custody, once again with the gun drawn.

"There's really no way to know how you're going to act when there's a gun pointed at you and when you think you're going to lose your life," said Gaston.

Gaston works as a defensive tactics instructor. He says he felt the best way to de-escalate the situation was to walk away. Eventually, Toledo police arrived after getting a 911 call. But the caller from inside the IRS office never tells 911 the man with the gun is a uniformed deputy sheriff.

Gaston's biggest concern as this incident unfolded were the other people in the office.

"If I'm going to get shot, like I thought I was, it's not fair. They came in there to do their business," said Gaston.

Gaston and his wife have now filed a civil lawsuit against that security guard Seth Eklund and the security company seeking compensation after Gaston allegedly suffered emotion and psychological distress and lost wages.

He's currently on medical leave from the Lucas County Sheriff's department. Gaston has a message for the guard.

"I would say ‘Clearly your training is lacking and the fact that you went 0 to 100. Lethal force is unacceptable," said Gaston.

13abc tried to reach Eklund for comment but we could not reach him. We have also asked the IRS for a comment but have not heard back yet.