For all you know he was sitting on her so she couldn't kick him anymore.
and Although HRU may THINK he was about to go off, perception is dangerous. You have someone swing and hitting and claw natural reaction is to defend. that doesn't have to mean beating up, but it could mean pushing her hands away which can look like getting ready to swing.
Really if she doesn't think he can drive then call the cops and let them deal with it. She probably had some knowledge of what his reaction was going to be.