I have a hard time with the words was (or is) followed by a gerund. In case anyone isn’t familiar with the grammatical term, a gerund is any verb turned into a noun by adding ‘ing’.
Used with the verb ‘was’, gerunds completely change the action (and tense) in a sentence. Implied in the phrase ‘was walking’, for example, is the additional phrase ‘in the process of’. Your character hasn’t yet completed the action of walking so it should read x was in the process of walking down the street.
Which means anything could happen before your character takes that next step. Maybe they will skip instead. Keel over dead. Who knows.
At least if someone is hitting your character, the potential exists for them to get out of there before the arm connects with their nose (or at least before the second blow hits).