I am a fully trained Ski Patroller. I would of course help with any of the seriously injured by stopping the bleeding. (Airway Breathing Circulation). I would be aware that terrorists quite often plant 2 bombs set to go off so that the second one gets the police and others who arrive to help so I would try to get my family out of harms way as well.
The logic process is this.
I see an accident. I assess the situation. Is there danger of further injury to myself or others? (yes may be a followup bomb) (yes the shrapnel from the bomb my be tainted with virus etc).
Remove your family from the danger of further injury by locateing them in a safe area. A safe area could be upstairs in a hotel or out a back door. Doing the obvious thing like walking out the front may be the worst thing to do if a car bomb is out there set to go 5 minutes later.
Assess the injured. Look for the most seriously injured first. Use ABC (Airway breathing Circulation) as your guide. Ie make sure they can breath and that they are not seriously bleeding. Do a quick once over the crowd and decide on the ones you can help. Use available resources by asking others if they can help you or if they have training. Get the ones that can help to assist based on their skill level and composure. Ie send the panicky guy to get help but keep the cool level headed guy to assist with the injured.
Oh yes and finally......
If one of the injured was French I would move on and go to the next injured person instead.
