Deserted under fire is a phrase that describes a situation in which people retreat from a war or battle, abandoning their post. Although this phrase is very specific, there are many synonyms that can be used to describe this situation. For example, some people might say that the soldiers ran away or fled. Others might describe them as retreating or withdrawing. These words all have slightly different connotations, but they all convey the same basic meaning. Other possible synonyms for deserted under fire include evacuated, abandoned, and routed. Ultimately, the specific word or phrase that one chooses to use will depend on the context and the writer's personal style.