Subtle, man. Subtle (says Greer)

[Arga]

Greer says "Subtle, man. Subtle" to Scott, when Scott is choosing people to form teams, to explore the ship.

I don't understand why Greer says it...
Can someone explain, please?

Is it because Scott apparently don't know, or pretend not to know James' name and Greer knew what they did in the closet?
It's the only explanation I can think of, but it's not obvious in the film.

[P-90_177]

Yep that's pretty much it in a nut shell. Gossip spreads on a small base. If Scott and James had been doing it for a while or even if Greer knew they had a thing for eachother then pretending they didn't know eachother would seem to him somewhat.........lame.