What are some ways to contain really bad anxiety in public places without having to make it obvious or leave the room?

I use fidget toys to curb my anxiety when in a public place. While some people question me while I fidget, they are usually very nice! Sometimes if I can, I plug in my earbuds and turn on my go to relaxing playlist!

Breathing exercises to start with. Focusing on something right in front of you to help you feel grounded. Counting Backwards from 10-1 or even 20-1.

Breathing in for 6 seconds, holding it for 7, and exhaling for 8! It's discreet and no need to step outside to do it.

Take deep breaths, count to 10, close your eyes and imagine that you are in your favourite place. Take yourself outside or to a quiet room wherever you are and you will feel better already. You could always sit down in a quiet corner somewhere and relax and chill. I'm sure nobody would mind. YOu should use mindfullness techniques such as deep breathing and stretching or saying your favourite word over and over again in your head. Ask someone nearby if they can sit with you for a bit so that you have someone near you. Or phone your friend on your mobile phone.

Really practice breathing patterns for relaxation. Get a fidget toy that's not too big and obvious, like the small cube,or rolling dice, with lil buttons and levers and such. Focus your anxiety and fidgeting on an external object you can "play" with, or really practice meditation at home, on the way to work, on the way to the event, notice your anxious emotions ahead of their escalation, know that you are in control of them, not the other way around. Do your best to appear smart and confident, stand up straight, be calm in your manners. Count your breathing and focus on the calming effects of it. Repeat reassuring words to yourself, such as "Everything will be fine. I just need to breathe. I will stay calm and collected. No one really pays too much attention to me, anyway.