Snacking on canned sardines in water (and drinking the broth) seems to work well enough, plenty of sodium. edit: Writing this comment has made me realize mixin

Snacking on canned sardines in water (and drinking the broth) seems to work well enough, plenty of sodium. edit: Writing this comment has made me realize mixing powdered dehydrated boullion into the water would probably work quite well too. The ambient temps are so high the water is basically at hot soup temperature as-is.