[Sonic thought back to his conversation with the present day Kalki, that she needed people to die to do what she needed to do with the crystal despite his own protestations...]

NO! There was no need for any of this!

[All of those people... and for him and so many others! He turns to the others, Captain Obvious moment or not]

When I talked to the Kalki of our present, she told me that the invasion was needed for a purpose. Now I understand what it is - those Crystals run on the power of the fallen and the more people are killed the more than can be used for other things!