First, you have to make a lot of points to open Lab “A” and “B”. Next, grab a bucket and filled it up with 115 water. Bucket can be found all over the map. 115 water can be found in Lab “A” near perk machine and lab “B” same as “A” near perk machine but you have to open the door to get access on the water. This is just for Lab “B”. Once your bucket is filled up, bring it inside Lab and pour it into the funnel. This will produce a temporary power that takes 1 to 2 mins before it turns OFF. Same on Lab “B”. Take note that you can use any 115 water.
Second, Bunker. Once you open the door, four zombies are waiting and one is going to transform into a Trasher.
Third, Power Room. Go inside the bunker and on your left theres a door. To make sure that you are in a right place. There is a name on the top of it. Once you are inside the power room, go straight down and swim. Look on your left where there is a web. Cut it out by press “F” (for PC users). Ten zombies will spawn and you will be lock out in this room. In order to get out, you have to kill all ten zombies. Once you manage to do those, you are free to go and the power is ready to be turned ON. Power switch is located on where you will see a green light panels, Its in the middle of those boards.