The same thing has been happening to me this week. I think the eternity soul thing has gotten more people interested in pvp. I'm noticing jumps of 100-200 ranks in a few minutes too. My guess is that everyone between rank 500-200 are all within 50 points or so. I can play one match and jump up 40-50 in the ranking.
Nodding Frogs gonna make some money this weekend. Between the eternity souls and the immortal souls, people will be buying a lot of ironite. I might even buy some if the drop rate of the event is decent.