By staying calm, you CAN get a face full of tear gas and get to safety. Pain is temporary. If you can't breathe, don't take gasping breathes. Push as much air out as you can, and take small, steady breathes until you're clear. Push out again, and then counted breathes. (1)
If you cant see, flicker your eyes until you can find the closest comrade. Grab onto them, communicate through words or signals you can't see. I've never had someone NOT guide me to safety. If you just keep blinking when out (it hurts yeah) your eyes will begin to clear. (2)
It hurts, a lot, and people have different experiences and tolerance to pain. But if you know what to do beforehand, you can be confident in your safety. You can clear your lungs and eyes faster, and lessen the effects. (3)
Focus your awareness outwards. What glimpses do you get when you can open your eyes? What do you hear? We begin to panic when we can't see, but you have other senses available to you. Just remember: this will pass, my community will keep me safe.
If you have an asthma attack or otherwise cannot catch your breath, your crew should be prepared to pull enough people that a group of... 10ish people can get you away and let you rest. If you need to go to the hospital, a personal driver will get you there faster than 911. (F)