I see, I like. Nice work so far Sroach. Those are clay and not concrete bricks, right? The reason I mention that is because I am aware that concrete can explode chunks if subject to high enough heat, though I do not know if the egg would get to that high enough temp.
Those bricks in the top pic (the other guy's) don't look like clay bricks, but rather concrete (or cinder bricks). Sroach's bricks look like clay, though. (I've got a pile of both in my yard, though the cinder ones are crumbling).
Cinder blocks have a habit cracking or shattering under high heat, but all concrete seems to have a bit of that tendency. I've found that both like to crumble as well, but that's normally due to frost - especially a lot of freezing/thawing cycles. In fact, I've found over the years that when it comes to any kind of brick, cracking due to frost is a lot more common than cracking due to heat.
But the heat it takes to shatter or crack a concrete block is pretty high. My fire pit is made from cinder block and I've measured temps of 750° internally when I'm burning scraps of wood like oak or tamarack. But with the shell of the egg moderating those temps, I don't think an Egg would get hot enough that it would crack concrete, let alone clay bricks.