Scenario You’re walking down the street and you come across a threatening group.

Advice Besides crossing the street, turning around and running away superfast like Benny Hill? “If you have to walk past them, remember that eye contact could be perceived as antagonistic,” says Anthony Celano, a former NYPD detective squad commander and CEO of Full Security, Inc. “But then again, if you look away, it makes you look like a victim. The trick is, look—don’t stare—and then look away, but do it nonchalantly.” (You might want to practice this a few times in the mirror.)

As for those situations in which contact is unavoidable, like when you’re trapped in the Tombs: “Try not to engage with the person,” Celano advises. “Look at them, but don’t stare them down. Keep an eye on them—don’t ever turn your back, because they could yoke you from behind. If they do get aggressive, don’t wait for them to hurt you—try and call a guard.”

All that talk of yoking has us in an aggressive mood; can we use these same tactics on a panhandler or that Greenpeace kid with the clipboard? “You don’t owe them anything,” says Celano. “Keep walking—do not stop. You don’t know what their motive is; it may be to intimidate you, or rob you, or sexually attack you. You don’t know.” So step off, Greenpeace kid with the clipboard. For real.

Scenario You’re on the subway and some scumbag keeps giving you the eye.

Advice Rather than snorting, scrunching your nose and giving them the stink-eye back, try a more subtle approach. “Sit or stand up straight,” says Mary Dawne Arden, a body-language expert. “If you slouch and look down, you’re perceived as more vulnerable.” If things get out of hand, move away—duh. “If you can’t do that, cross your arms,” says Arden. “Don’t shake your leg or foot, though—it shows that you are nervous.” And finally, wear an iPod—it’ll send a clear signal that you’re not to be messed with, right? “No!” counters Arden. “Above all, stay focused in present time. If you are distracted or multitasking with your BlackBerry, cell phone or iPod, you won’t see trouble coming until it is on top of you. And that makes it so much more difficult to protect yourself.”

Scenario A crazy person starts screaming, invading your personal space and alarming everyone around you.

Advice Your usual stare-straight-ahead-and-pretend-like-nothing’s-going-on trick pretty much works. “I surveyed my patients, and their advice was either to stare straight ahead and not respond, or get up and move away,” says Dr. Alan Manevitz, associate professor of psychiatry at New York-Presbyterian–Weill Cornell Hospital. “I would say, if you feel unsafe, try to remove yourself from the situation. Otherwise, use common sense and follow your instincts. In general, be hyperaware: Don’t panic, and don’t take it personally. If you’re confronted by someone, you generally don’t want to engage. The person is already agitated. It’s a split-second decision; you may want to say ‘Sorry,’ lower your head and remove yourself from the situation. You may just want to ignore it and move.”

As for the folks who simply won’t be ignored, Manevitz recommends a combo of subtle body language and what sound like tricks from every hostage-negotiator movie ever. “Make sure there is at least three to six feet between you. Project calmness, and speak slowly, quietly and confidently,” he says. “Maintain a relaxed, attentive posture, and position yourself at a right angle rather than directly in front of the other person. And respectfully ask the agitated person what the matter is, acknowledge their feelings and indicate that you can see they are upset. Use statements like ‘You’re probably right.’ As soon as help arrives, let the trained professionals handle the situation.”