What's unethical? Depends quite a bit on your definition of ethics, even if ground rules like 'killing or hurting people is a bad thing' is agreed upon. The problem is one of balancing the risk and reward. The acceptable ratio varies from person to person, as well as the estimates for each. Collateral damage, for instance, is inevitable in war, and while such damage is clearly wrong, it isn't necessarily unethical. So saying that there is absolutely no justification to engage in unethical behavior is either trivially true, or false.

I happen to agree with your (I presume) belief that the suppressing the secrets in this case will have a higher cost than revealing them, but there is a reasonable argument to the contrary.