So, let us give Phoebe credit about what she says even if she talks about Marlowe’s “H&L” as if it is “an amorous poem”. First she tells her boyfriend Silvius that there is no such thing as “murderer’s eyes” or a force in eyes that can “do hurt”. But then she encounters Ganymede who changes her thinking. She remembers what he had to say to scorn at her and she determines to answer “taut pour taut” what with a “very taunting letter” that is written in a spirit of “omittance is no quittance”. Thus she answers Ganymede’s “As by my faith, I see no more in you than may without candle go dark to bed” what with “Whiles the eye of man did woo me that could do no vengeance to me” meaning Shakespeare’s Ganymede is “a beast” like Marlowe’s Ganymede as to a Leander turned with “murderer’s eyes” and if he does not stop scorning her like that and find out what she “can make” then she too will “study how to die” as in compare. That is to suggest Phoebe hears him compare her to Hero and she responds by comparing him to Leander.
Touchstone is key: “When a man’s verses cannot be understood” Leander admires Hero after she makes her “false morne”. But when Marlowe’s verses can be understood, Leander admires Hero before she makes her “false morne”. After she makes her “false morne” Leander scorns Hero which is what Phoebe alludes to in her rant and then again in her subsequent “very taunting letter” wherein she compares Shakespeare’s Ganymede’s scorn of her to Marlowe’s Ganymede to a Leander turned scorn of Hero. The difference between her rant and her letter being the fact that her encounter with Ganymede changes her understanding of Marlowe’s verses. Whereas prior to her encounter she gives the lie to it, but after her encounter she affirms it what with an aside that comes in between her rant and her letter to signal she no longer endorses the lie she claims in her rant. A point here being that when Marlowe’s verses can be understood after Hero makes her “false morne”, Leander does what Phoebe writes about in a letter written in the spirit of “omittance is no quittance” and what she writes about in said letter is what Touchstone refers to as “a great reckoning in a little room”.