“let’s perish there...doomed us to perish.” The Hebrew word translated “perish” is silence, so the phrases are more literally, “let us be silent there...put us to silence.” “Silence” in this context refers to the silence of death (cp. Ps. 94:17). Many versions translate “silence” as “perish” because it is not clear in English that “be silent” means “be dead.” That the men would yell, “let us enter into the fortified cities, and let us perish there,” is a cry of desperation, a cry of men who know they are about to die and want to make a desperate move to possibly save themselves from the “poisonous water” from Yahweh that is coming to them because of their sin.
“given us poisonous water to drink.” Poisonous water is also mentioned in Jeremiah 9:15 and 23:15.