וַיִּנָּֽגְע֛וּ יְהוֹשֻׁ֥עַ וְכָל־יִשְׂרָאֵ֖ל לִפְנֵיהֶ֑ם וַיָּנֻ֖סוּ דֶּ֥רֶךְ הַמִּדְבָּֽר׃
E Giosuè e tutto Israele fecero come se fossero stati picchiati davanti a loro, e fuggirono per via del deserto.
Rashi on Joshua
Pretended to be stricken. This is an expression of נֶגַע, plague, or beating. They gave the appearance of being beaten before them.