Teddy Henfrey entered the parlor because he had been commissioned by Mrs. Hall to take a look at the clock. She claimed that, although the clock seemed fine, the hour-hand would point at nothing but six o'clock. Mrs. Hall was actually getting ready to go and ask the stranger whether he would like some tea, but she had yet to muster up the courage to do so.
When Teddy Henfrey, the clock-jobber, came in at about four o'clock, Mrs. Hall saw an opportunity to kill two birds with one stone. First, Teddy's company would definitely bolster her courage in her quest to find out more about the mysterious stranger (and to extend necessary hostess courtesies such as inquiring about a guest's eating habits and preferences). Second, the clock job would be an alibi for Mrs. Hall's curiosity and no one would be the wiser for it. With such satisfactory pretenses, Mrs Hall precedes Teddy Henfrey into the parlor.
When the stranger protests that his privacy has been invaded, Mrs. Hall tries to reassure the stranger that they are only there to see to the mending of the clock. After a terse exchange about the stranger's boxes at Bramblehurst (he wants them brought over as soon as possible) and the stranger's confession that he is an experimental investigator, Mrs. Hall leaves the room. Meanwhile, Teddy Henfrey, his own curiosity getting the better of him, tries to 'work in as slow and quiet and unassuming a manner as possible' in order to delay his departure from the parlor and perhaps, fall into some conversation with the stranger.