if ur protesting revise the area before you go, look for a safe place to run to.
also memorise a phone number of a contact close by, if you can’t, write down the number on paper and put it in your underwear.
turn off face/thumb ID on your phone and any other way or collecting-

data from your phone (turn on aeroplane, bluetooth, auto wifi join).
make sure notifications can’t be read from the lock screen, disable the swipe up menu on your phone.
organise with an outside contact certain time intervals where you text them to let them know your okay-

after you have texted them, turn back on aeroplane mode. turn off airdrop and hotspots. you could also organise code words or quick words to type incase you’re in an emergency. if you have keys with you don’t carry anything with your address

also if your locks even has anything that can easily make you identifiable, change it.
clear pockets of things like receipts and keep things like ID secured and out of reach