Consider is including ear plugs, aspirin, menthol cough drops, and something that will work as a sleep mask. There are situations where your going to be stuck in close proximity to other people.
Small in-ear plugs still allow you to hear conversations and warnings because they only dull the noise.
Menthol cough drops mask the inevitable smells associated with numbers of people tightly confined and help slake thirst, and cure an itchy throat. They may also help smokers who are confined where they can't smoke and help calm cranky children.
Aspirin are good for tension headaches and might save a life if someone has a heart attack.
Pop in the ear plugs, add a cough drop, and put on your sleep mask and you can go into your own little world while still maintaining enough awareness to be safe. If the situation is very much under control you might catch a nap.
This should also emphasize that it is best to travel in clothing that is comfortable, durable, and protective. Sturdy shoes, I prefer boots, that you can hike in and leather gloves are helpful.