User blog comment:AYET/AY's Chapter 669 review/@comment-85.24.209.78-20120530164154

"I don't quite get the first two panels of page 15 (behind Caesar's lab), was it "a room appear and Law with Chopper just appear there out of nowhere"? So does it mean that Law can teleport from anywhere to anywhere? Handy!!!"

http://www.mangareader.net/one-piece/669/15

Actually, from the looks of it Law just teleported from the hole down to ground, thats at least how it looked to me.

Also, Law saying he can't do anything to Caesar because of a 'problem', I don't think it has anything to do with Haki. Maybe it has something to do with, as you said, his crew, maybe his (Caesar) DF or something else...