Once safely alone in the cab, Lily berates herself for her indiscretion with Selden. Mostly, she thinks it's ridiculous that a woman can't enjoy herself for two seconds without getting in trouble for it.
Then, she realizes she's a fool for not just telling Rosedale the truth. By making up that story about her dress-maker, she made it sound like something fishy was going on, when in fact she only had tea with a friend.
She's also an idiot for not accepting Rosedale's offer as an escort, since snubbing someone who's got dirt on you is a bad idea. She knows that Rosedale is a big social-climber, and that being seen with her would do wonders for his reputation.
Lily is particularly worried since Rosedale makes it his business to know everything about everyone, and he's kind of a gossipy guy.
She remembers when her cousin, Jack Stepney, befriended Rosedale and got him into some big parties thrown by the fashionable Van Osburghs. It didn't go over well. Rosedale was rejected for being new money and for being Jewish. But Jack was undeterred, knowing how valuable Rosedale would be in the future. (In other words, Jack knew Rosedale was on his way to making lots and lots of money, and that it was prudent to make him an ally early on.)
Lily gets to the station and settles in on the train to the Trenors'. Looking around, she spots Mr. Percy Gryce, whom she zeroes in on as the perfect travel companion. Lily pretends to notice him when she's walking by and takes a seat across from him after confirming that he, too, is traveling to Bellomont.
The two of them share tea. Lily realizes that Percy is shy and painfully inexperienced in conversing with women, so she steers the conversation toward a topic he'll be comfortable with: Americana.
Remember Selden's discussion of the Jefferson Gryce collection? That was Percy's uncle. He died and left everything to Percy – lots of books, lots of cash. This explains Lily's interest in Percy…
Percy is ecstatic to have 1) someone to listen to him talk about Americana, and 2) someone who isn't falling asleep listening to him talk about Americana. Also, Lily is gorgeous, which doesn't hurt.
Meanwhile Lily is calculating how long it will take to get Percy to marry her. He's one of the most eligible bachelors around, on account of his money.
We hear the general back-story on Percy and his upbringing, which we can sum up in two words: mama's boy. Mrs. Gryce brought her son to New York to install him in all the right circles, and Percy's current occupation is accumulating as much wealth as possible.
As the conversation continues, Lily feels as though she's in complete control.
Unfortunately, at the next train stop they are joined by Mrs. George Dorset, who takes the seat next to Lily and ruins the tête-à-tête.
She asks for a cigarette from Lily, who exclaims with shock that she doesn't smoke. (This is, of course, for the benefit of goody-two-shoes Percy.)