This paper investigates QoS routing in an ad hoc network applied to a multi-robot network system named the "victim detection system" proposed for detecting victims in urban disaster areas. For the purpose to secure the survivability of victims, a modified frame structure is examined in this paper based on the already proposed method: synchronized QoS routing. This modified scheme improves the network performance of victim detection system including rate of successful communication, call setup time and transmission breakage interval. These improvements are confirmed by computer simulations.