She KNOWS she's about to be hung out to dry by her boss.
He already told Schumer it was her fault.
So no matter what, she's screwed.
She's probably not high enough in the chain to warrant being a GW buddy, which means no pardon for her on his way out the door.
So she has to cut a deal.
And the only way she can be sure of total immunity is to clam up right now, and hope there is not enough circumstantial evidence to take her out anyway.
And they want to work up the chain, so if she's the link, she's golden.