I've had one apart. My XL when it smoked :-)
There is an upper and a lower half, both connected to the outter row of FETs top and bottom on the board. The thermal adhesive used to to retain the halves gets soft when heated (or in my meltdown just turns to grease).
I'm sure you could heat the ESC to ~200'f with a heat gun and it would come apart without significant risk to the FETs. You would of course be voiding the warranty.
I'll likley pull apart a ICE HV 80 in the next few months to make an ultra small HV with liquid cooling. I'll take lots of pics and maybe a video of it while it's apart...