 Unable to decipher Nedry 's code to reactivate the security system , Hammond and the park 's chief engineer Ray Arnold opt to reboot the entire park 's system . The group shuts down the park 's grid and retreats to an emergency bunker , while Arnold heads to a maintenance shed to complete the rebooting process . When Arnold fails to return , Sattler and Muldoon head to the shed . They discover the shutdown has deactivated the remaining fences and released the raptors . Muldoon distracts the raptors while Sattler goes to turn the power back on before being attacked by a raptor and discovering Arnold 's severed arm . Meanwhile , Muldoon is caught off @-@ guard and killed by the other two raptors . 
