Spitting

[misto]

saliva should react with most chemicals much like water does.

frankly, so should blood, and a person should be treated as a partially water-filled target on injection for chemical reaction purposes. but this might make some chem terrorist mixes even nastier

Okay, but on the other hand if you were to do that bananas would become literally inedible because they would explode when you try to eat them

then perhaps the reaction threshold of that reaction should be raised rather than any tiny bit coming in contact with water resulting in an explosion. bananas are a moist fruit, there is naturally some water content in there, and yet they do not explode willy nilly