You can carry a cheap second phone with battery removed (airplane mode is not sufficient) for this purpose specifically. In case you must call someone, you put in the battery and call.
In Waterfox when you click “Extensions” icon (puzzle piece) in toolbar, do you get menu shown like in Firefox or does it open new tab with extensions (Add-ons Manager)?
(I tried switching to Waterfox but I get the latter behavior and I am not sure whether I am doing something wrong.)
You can carry a cheap second phone with battery removed (airplane mode is not sufficient) for this purpose specifically. In case you must call someone, you put in the battery and call.