After a bomb detonated at a concert in Manchester, England, killing and injuring dozens, KIRO-TV asked a retired FBI agent what he thinks about and prepares for at large events.

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Retired FBI agent David Gomez said people should think about the following before attending a concert, sporting event or large gathering:

1. Don’t push through crowds to exit at the end of the show.

While many fans are eager to beat the traffic, Gomez said he intentionally hangs back.

“I’m usually in no hurry to leave. Let the big crowds progress first. Let me have a clear space where I can watch,” Gomez said.

He said it’s harder to be aware of your surroundings when you’re shoulder to shoulder with the crowd. If someone on the outside is waiting to target a large group of people leaving a venue, the person will generally attack the first wave of people out the door.

2. Before the show starts, find the closest exit.

Before the concert starts, look around for the closest exit. This might sometimes be a door toward the back of the venue, away from the doors where people entered.

Gomez compared it to the way he sometimes chooses where to sit in a restaurant: “We pick a table that’s away from the front door and close to the exit, rear door, so I know if somebody’s going to come in the front door and rob the establishment, or is going to shoot somebody in the establishment, I have an exit that’s not close to the front door.”

If someone enters through the back door, Gomez said he still has a clear line to the front door.

3. Note the security staff closest to you.

Know where they are in case you need to report suspicious activity or ask for help. In case of an emergency, they will likely be issuing instructions.

4. Discuss a meeting place for your group if you get separated.

Make plans ahead of time so that if you are separated from your party, everyone knows where to meet. Members of your group should know that the spot might be adjusted if there is a threat inside the venue vs. the outside.

5. Observe who and what is around you -- not what’s on your phone screen.

Matthew McLellan, a student on Mercer Island, told KIRO-TV he has attended concerts where many people are on their phones. He said he likes to send Snapchat photos to share his concert experience.

But McLellan said that because of this week’s attack, he’ll be thinking twice.

“It was shocking,” McLellan said. “Just seeing the numbers (of casualties) increase every couple of hours just hurts me.”

6. If something happens and you can’t find an exit, shelter in place.

Gomez said one girl who attended the concert in Manchester was reported to have stayed in her spot on the third level of the venue because she couldn’t find an easy way out. Police eventually entered the building to help people get out.

7. Before you go, check the venue website for specific entry rules.

Some venues require clear bags only; some performers specifically call for no use of cellphones. Read the information on your ticket and on the venue website carefully before you leave the house so you won’t be turned away at the door or kicked out.