Hartwell disguises himself as Startup, and the Nurse unknowingly leads him to Frances's room. Frances recognizes him, but pretends to believe that Hartwell is Startup, and pretends likewise to be receptive to his suit.
In this scenario, Hartwell adopts an alias as Startup, and the Nurse inadvertently leads him to Frances's quarters. Frances identifies him, yet pretends to be receptive to his proposal, adopting a similar demeanor he had previously used.