The antonyms for the phrase "became immobilized" are words that describe the opposite of being still or unable to move. Words like "active," "mobile," "flexible," and "agile" are antonyms that describe movement, flexibility, and agility. These words indicate an ability to move freely and easily, without being restricted or hindered. Antonyms also include terms like "energetic," "dynamic," and "animated," which suggest a lively and energetic state. "Free," "uninhibited," and "unrestricted" are also antonyms that suggest a lack of constraints or limitations. These opposing words highlight the freedom and flexibility that comes with being agile, active, and mobile, in contrast to being immobilized.