Who comes to the door just as Mrs. Joe is inviting the guests to taste her pork?

Joe Gargery, Pip, and their assembled guests have just sat down to sample one of Mrs. Joe's legendary savory pork pies. But Pip isn't looking forward to it. In fact, he's filled with terror. For there is no pie; he stole it from the larder and took it to Abel Magwitch, cold and starving out there on the Romney Marshes.
Pip cannot stand the tension; he knows his theft will soon be exposed. And Mrs. Joe has just discovered that the pie is missing from the larder. So Pip starts to make a run for it. Suddenly, there is a knock at the door. There's a group of soldiers there and Pip runs right into them. The sergeant is looking for a blacksmith to fix a pair of handcuffs. They are out searching for escaped convicts, one of which, of course, is none other than Abel Magwitch.
The sudden appearance of the soldiers at the door has allowed Pip to escape a beating from Mrs. Joe. Later on, as he witnesses the apprehension of the two fighting convicts, Abel Magwitch falsely confesses to having stolen some items from Joe Gargery, including a savory pork pie. This is a huge relief to Pip, who is now completely in the clear.