So I've recently gotten the Graviton Lance's catalyst and one of the requirements is to get Cosmology kills. Judging from how the Polaris Lance's catalyst worked, I'm assuming that the seekers have to kill enemies to progress the bonus, and it seems like it needs about 200 kills to complete. With all of that in mind, are there any good spots that would help rack this up quickly? The only good place I know of so far is grinding Thralls during EPs and even that only gives out a percent or two per wave.