There are four hacking consoles (panic buttons), one in each corner of the room. You start out the challenge by finding the yellow one and hacking it. Once you do this, a symbol will appear on the big screen at the end of the room. This symbol will match one of the 8 symbols by each pad. You want a team member to step on the pad that has the matching symbol. Once they do this, the pad will turn blue and the symbol will disappear from the big screen. Repeat this until each member of your party has activated a pad. Once the last pad is activated, the door under the big screen will unlock and everyone can get off their pads.
Extra: Make sure you brief your teammates on the challenges beforehand. If you haven't figured it out already, stepping on the wrong pads will instantly down you. If you are midway through the challenge and someone steps on a wrong pad or gets off a blue one, everybody standing on a "good" pad will be electricuted. The easiest way to achieve this challenge is to have one person in charge of hacking and have them call out who goes to which pad.