The phrase "be in sequence" implies that something is happening in a particular order or pattern. Antonyms for "be in sequence" include "be disorderly" or "be chaotic," suggesting that something is happening in a random, disorganized way. Another antonym could be "be discontinued," meaning that something is happening at irregular intervals or not at all. "Be out of order" could also be an antonym, indicating that something is not happening in the expected or desired sequence. In general, antonyms for "be in sequence" emphasize unpredictability, disorder, and lack of structure.