Why Ozymandias opened his vivarium?

In Chapter XII of Watchmen, Ozymandias opened and thus, destroyed his vivarium.

I cannot see a meaningful reason behing that. I believe he didn't destroy it per se and there must be a meaning of that, but still – cannot figure out why. I have some thoughts and theories about that but none of them are convincible enough.

Is there any explanation why he would did that?