Running off is a term often used to describe a situation where someone is leaving quickly or suddenly. However, there are many synonyms that can be used instead of running off, such as fleeing, escaping, bolting, darting, sprinting, dashing, or rushing away. These words can be used to describe situations where someone is leaving due to fear, excitement, or just in a hurry. If you want to be more specific, other synonyms such as absconding, eloping, or evading can be used to describe situations where someone is leaving with an intention to avoid or escape something. Overall, there are plenty of words you can use instead of running off, depending on the context of your sentence.