“And I said, ‘Well how are you going to get it out of the cloud,’” Greene recounted at a Fortune Most Powerful Women dinner in San Francisco on Wednesday.

The story illustrates the ways that technology is “moving faster than the regulators can move,” Greene said.

A big part of her job is educating regulators, she added. That’s particularly true when it comes to artificial intelligence—a technology that’s provoking a great deal of anxiety.

“Where the fear of A.I. comes in is you have a technology that can do things that are human-like,” she said. “It recognizes and sees things that didn’t exist before.”

Google itself was recently involved in an A.I.-related controversy over its contract with the Pentagon’s Project Maven, which uses the technology to improve the accuracy of drone strikes. After an internal backlash, Greene reportedly told employees that Google would complete its contract but insisted that the technology would be “consistent” with the company’s principles and not be used as weaponry. Greene also said that Google does not plan to renew the Maven contract.

During the Fortune interview she said Google’s A.I. researchers care deeply about developing principles about how their technology will be used.

She equated the position that tech companies are in to governments that are making constitutions about how they’re going to operate and what their values are.

“You have to talk about what the worst possible use of a technology is,” she said, “and say whether or not that’s okay.”