Power Surge is a location-based challenge in The Holodome Onslaught. To perform this challenge in The Holodome, an enemy must be failed into the central pit of the Holodome. It is worth 5 Badass Rank.
Using an under-leveled Oz Kit to slam an enemy into the pit is one viable strategy. Alternatively, if the Vault Hunter stays on the lower level near the pit, it's likely that an enemy will end up falling in of its own accord, without any assistance from the Vault Hunter.