Get a group of 4 human characters (Jack does not count).
Start Asylum on wave 41, the 4 taps will be available to activate. Asylum is a good map as the 4 taps can be seen from each other so you know when every one is in place. Activate the 4 taps and complete the wave.
Once wave 42 starts (can be before the count down is finished) have each player choose their own tap and withdraw the energy. You should be able to get all the energy before the wave starts.
The achievement may to 30 - 60 seconds to pop.