Here are some simple tips if you find yourself in a terrorist attack

No one who has never been in or close to a violent situation really knows how he or she will react to the experience.

No one who has never been in or close to a violent situation really knows how he or she will react to the experience. From my time in war zones in Chechnya, Afghanistan, and elsewhere, I know that you might find yourself completely calm or, more likely, in a terrified panic; things will happen so fast, you probably won’t know what to think, and could freeze up.

There are no guaranteed methods of survival. But there are simple guidelines that could help.

This is easy to say, but the first thing is try not to panic, and tell anyone with you the same. Stay clear headed. And don’t make yourself into a hero: If there is shooting, go down flat. If possible, shrink yourself behind something, especially if it’s concrete. In a bombing, get prepared to move fast.

If you naturally seem to be accepted as the leader of any friends or family you are with, be decisive, but do not struggle for control—you want to operate as a unit. If you and your group are okay, see whether there is anyone you can immediately and quickly help, either by attending to an injury, or calming them down. Meanwhile, stay out of the way of others who are also attempting to get things done.

Here is solid advicefrom people present for last November’s attacks in Paris. The gist: keep your wits about you.

All the while, look for an exit. Is there a nearby way out? If so, take it rapidly and quietly. Others are likely to follow you.

If you are trapped in a building but can move, look for a place to hide. Take a look at this video, produced by the British Police Chiefs Council in December, on how to reach a hiding place and what to do when you get there.

Once you are out of harm’s way, look again for any help you can offer. If you have intelligence from anything you observed, find law enforcement and report it as fully as you can. If there is none, stay out of the way of emergency personnel; do not gawk; and leave the area, as another attack could be unfolding.

If you have become separated from your group, send a text message. Do the same with a family member or friend elsewhere so your loved ones do not worry needlessly about you.

Should you rush a gunman? If you are militarily or otherwise trained, you might look for such an opening. We have an example of that in August 2015 when three Americans—including two servicemen—stopped an attack on a French train by rushing the gunman. But generally speaking, that is a last resort.