Hmm..
I think Misery probably destroyed the egg corridor. Summoning those bomb clouds, basically she just wrecked all the eggs that she could find. [Luckily for Kazuma, he probably already hatched the sky dragon to escape, and got out of there before Misery showed up. Either that, or Misery just didn't see the egg since it was in a seperate room; and Misery probably just nuked the place and thought she got everything.]
Why Misery? Well, remember Booster and Sue just got captured, along with chomp,chomp the mimiga (Sue told him and who knows who else about the Dragons.) When you leave for the Sand Zone, Kazuma said I think says something about securing the escape route.
"Kazuma" said:
After you left for the Sand Zone, the rest of us hurried to secure a means of escape. That's when Misery showed up. Sue got taken off with her, and I haven't seen the professor...
Okay after reading the quote, that pretty much settles it I think... Misery found them while they were securing a means of escape [probably Egg Corridor], blew the place to pieces, taking Sue and Booster... [but Kazuma got away!]
I don't think the Egg Corridor belongs to the Doctor anyways. Remember Igor? He said DON'T TOUCH MASTER'S PRECIOUS EGGS. I think Igor is probably referring to Miakid, the last Demon Crown owner (from the war). The Doctor hadn't even seen the Red Flower before the storehouse from his dialogue... "So that's the Demon Flower..." or something "would you like me to test it's effects?" "No... feed it to a Mimiga instead."
So, I think Igor has probably been around since the 10 years ago. There might be red flower petals around the bed; but that just means maybe he grew his own red flowers? The flowers were in the control monitoring room for the eggs. So I imagine he's been running the place while the master was gone... Who knows maybe he'd have fed red flowers to Sue if he had the time to. Who else would be crazy enough to hide the ID card and computer inside an EGG! And remember the forcefield was up when Quote got there, but Igor and Sue were already inside... so he knows about everything; even if he's crazy. Is Igor wearing a tie? or a necklace? hmmm...
Anyways yeah I think the Egg Corridor was used by Miakid to make Dragons attack... As for zombie dragons... what if... the eggs had been fed Red Flower stuff? I mean how else would they be Zombie dragons... I think he was up to no good. Maybe only egg 00 was raised properly..? Well a theory anyways.
Oh btw my original theory was that Kazuma caused the explosion accidently xD But, my above one makes more sense now.
(Extra theory : Personally I think the Sky Dragons used to inhabit this island quite a bit, and maybe before the scientists and humans came 10+ years ago..) Dating back to the crocodile/old dragon Crown Bearer. No proof, but since Sky Dragons exist on the island... I might be led to believe once upon a time perhaps there lived MANY more. My personal theory anyways... [Imagines a giant dragon boss for the 2nd crown bearer...]
Alternative theory : With Igor gone, and nobody to monitor the eggs, all havoc broke loose?