Every Monday, Graves needs to go talk to his former captor and rapist, getting every bit of information Grindelwald will give him. After every interview/interrogation, he goes back to his office, planning to immerse himself in paperwork. Every time, Tina's there with a bottle of gin for them to share. Because she's the best employee/friend (please not girlfriend/lover) ever.

Bonus if Madame Picquery knows about Tina and Graves drinking sessions and knows that Graves probably won't get anything done after he leaves the interrogation room, but doesn't say anything because she figures that giving Graves the rest of Monday off after he lets himself get put through hell for MACUA is the least she can do.