Dying Light SUPRISE MFs!!! Location Guide
This well hidden blueprint add electricity and toxic damage to your weapons. It can be found on the very top of a bridge pillar in the slums. If you come to the pillar of the bridge you can see some rails you can grab onto. This is the path you want to start out.
For the most part there’s only one way to climb up and it’s marked pretty clearly. You want to take your time on the top level, because there are a few jumps and climbs that can easily result in falling and often this means starting over.