Secret Service faces scrutiny over attempted assassination of former President Donald Trump

When the shots were fired on Saturday at former President Donald Trump during a campaign event in Pennsylvania, it was the worst-case scenario for the U.S. Secret Service.

The Secret Service's major aim is to protect the president, under the motto, "worthy of trust and confidence."

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As protesters converged peacefully on the Republican National Convention in Milwaukee Monday, avoiding another violent event is now the Secret Service's mission.

Two months earlier, at Secret Service headquarters in Washington D.C., the ABC7 Chicago I-Team spent time with director and suburban Chicago native Kim Cheatle .

SEE ALSO | ABC Exclusive: Trump rally shooting 'unacceptable,' Secret Service director says

Cheatle discussed the service's tactics in Milwaukee and in Chicago this summer for the Democratic National Convention, as well as her greatest fears, from biohazards to domestic terrorism.

"Our job in the Secret Service is to make sure that we cover all of those potentials, whether that be, you know, demonstrations, whether that be intelligence threats that are driven out there," Cheatle said.

Cheatle and other security planners know that no protection plan is ever 100% certain, but an assignation attempt at a campaign rally seemed hardly on her radar.

With a congressional appearance looming, some are already calling for Cheatle's resignation.

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In an exclusive interview with ABC's Pierre Thomas , Cheatle said she has no plans to step down.

Cheatle said on Monday the assassination attempt was "unacceptable" and that her agency will perform a review to ensure Secret Service personnel are given necessary resources to fulfil their duty.

Some of Cheatle's words shared during the I-Team's interview in May now take on a different meaning.

"We are always monitoring, you know, what threat streams are out there," Cheatle said. "I will say that the Secret Service and the Chicago Police Department, as well as all of our other partners, certainly respect the right for people to be able to demonstrate peacefully. You know, it does become a challenge if those demonstrations become violent. And unfortunately, sometimes you may get a bad actor or two that kind of, you know, will lead the crowd that way."

SEE ALSO | Secret Service, Chicago police responsible for securing rooftops around United Center during DNC