It's not "bad" that you want to wait for him to come back and see what he has to say, but it will be the point you look back on in future and wish you hadn't.
It will be you turning towards the situation instead of turning your back on it for your DC sake and getting you both away.
It will be the bit where he makes you wait just long enough so you've had plenty of time to doubt what happened, question your own sanity and begin to feel it must be your fault that he hit you. Because he did hit you, and it was not your fault. You did not "deserve it".
It will be the part in the story where he comes back, minimises it, gives some shitty excuse, tells you that it wont happen again, he may even turn up with a shitty bunch of flowers from the petrol station.
It will be the time you look back on in future after yet another episode of violence, possibly in front of your DC and wonder why you didn't run the first time it happened.
Do it for your DC, if you can't do it for yourself, there is no happy ending with him.