[Ozymandias] Why did Veidt destroy his utopia?

[butabi44]

I've read WATCHMEN a number of times now, and love it with greater intensity each time I do. I did have a question maybe someone here could answer:

After he kills his Vietnamese servants with his Vivarium, Veidt opens the dome to his utopia "alien world." Why would he do this?

I feel like the only reason would be because he knows Dan and Rorschach are coming, and wants to conceal that fact that he murdered his employees... but then later he reveals that everyone involved with his plan is dead...

...can anyone help me?

 

[The Guard]

It's symbolic. He says something earlier in that chapter that points out what the utopia represents to him, and when he destroys it, that is representative of something as well. I can't remember his exact words. Something about a fragile pane of glass...