Of course she had a nursery built into her office. She wants her kids to watch Mommy finish augering a major company right into the ground.
Yep - that's what her mission from Google is! I'm amazed people don't see this. Her job is to take over and destroy Yahoo from within for Google - she's Yahoo's Obama. Whether by bankruptcy and collapse or a takeover scenario by Google or a Google ally, that's what Mayer is there to do.
At which point Google will welcome her back as president of Google.