In the Great East Japan Earthquake of 2011, some elderly evacuees who couldn't travel a long distance to a safe place by themselves were late and harmed. Some healthy people who picked other people up to evacuate but some helpers' evacuations were delayed and also harmed. This paper proposes a dynamic control approach of pick-up behavior to obtain minimal risk of an area. The approach evaluates an effect to earlier evacuation by pick-up behavior and evacuation delay by road congestions dynamically. Our deductive and sequential optimization algorithm can reduce their calculation cost as much as possible because the algorithm doesn't utilize future forecasts. Numerical results show that the dynamic control of pick-up behavior is effective in the decreasing their risk in a tsunami disaster.