Yeah, I think it's... it's quite strongly mixed here because on the one hand, he is pretty much decided to leave the company and May Grey won't be very pleased with that. But on the other hand, he's also been very open about it, because he may wanna come back some day. And I think, she is glad he's been opening clear. So, she is sort of thanking him for that and she is also understanding his position at the same time.
2) In a discussion or an argument, this phrase means "I head what you said, but I disagree."
3) on the surface "On the surface" is a nice useful phrase meaning I haven't looked into
is "at first glance." A similar phrase is "superficially." But, superficially is usually used when you are saying it's only the surface and that's a negative point.
4) devil's advocate 悪魔の代理人 In stead of "take on the role of devil's advocate, many people say
But, a "devil's advocate" is interesting also. First of all, "advocate" means a backer or supporter generally and specifically can also mean attorney or lawyer. The phrase "devil's advocate" though, usually describe somebody who's supporting the opposite argument for the sake of argument by arguing by discussing two sides of some issue. You can lean more about the issue or you can test the argument that's you really support. So, playing devil's advocate is like supporting the devil, it's taking up the other side.
5) So, here's an example of Grey playing devil's advocate. Usually, this would be a pretty aggressive question to ask someone who just said they were pretty much decided to move to a new position. It almost sounds like she thinks he can't look into the new job on his own. But, because she already said she was gonna be the devil's advocate for his decision, it's OK for her to ask hard and direct questions.
6) It's a good thing that Grey decided play the devil's advocate, because he's already found an area that Takahashi hasn't looked into very carefully that is about the culture of the company he's thinking about joining. He begins by saying frankly, although phrases he could use include, "to tell the truth," or "actually," it depends on how formally he wants to express himself.
7) Takahashi-san also talks about leveling with the people who might become his new team members. Level with is very informal way to say talk openly or frankly, but sometimes if you look at someone and say, "I'll level with you," it's usually a signal that they are going to tell you something you don't really want to hear.