Once an aircraft touches down on an unprepared surface all bets are off. Fire can happen easily. The plane may stay upright with no injuries, or the aircraft might flip and kill everyone. One person can walk away unscathed while the guy sitting next to him might be dead -- it's a crap shoot.

Get a good FAK to handle immediate emergencies like profuse bleeding. Do what you can to get rescue there quickly and let the EMT's do the heavy lifting. $.02