They could have done what they thought was right in the interests of the Internet as a free, unregulated medium and by extension their business which depends on the Internet, even if that course of action (or inaction) was not clearly legal. Then they could have used some of their billions in cash on hand and their team of lawyers to defend themselves against prosecution. They, instead of some random sysadmin, could be the ones bringing this issue of Internet spying to the fore.
Now, before you say "What, do you expect them to break the law?", consider that they routinely push the boundaries of US law (securities law, copyright law, tax law, etc.) and lo and behold they are usually successful.
Now, I expect you might say "What you're suggesting is still nonsensical because resisting orders related to national security is, among other things, far too controversial and not in the interests of shareholders." And I would not disgaree with you.
My point is simply that Google, with its vast resources, is in a much better position than Ed Snowden to take on this fight for the future of the Internet and privacy of communications.
You could even argue Google has more skin in the game than Mr. Snowden, or any of us individually (aside from those who exploit others' private information for profit, of course)... because if this controversy brings about knee-jerk changes in privacy law, it could materially affect their bottom line.