I think at this point in the book Aunt Alexandria has been spending more time with scout and answering Atticus' promise of giving her feminine influences
Duncan (the King of Scotland), his two sons (Malcolm and Donalbain), and Lennox (a Scottish nobleman) hang out with their attendants at a military camp in Scotland.
Lost? Check out this nifty map of major locations in the play.
King Duncan's forces have been busy fighting against the King of Norway and the traitor, Macdonwald.
A wounded Captain arrives, fresh from the field, where he fought to help Duncan's son, Malcolm, escape capture. What's the news?
Well, says the Captain, the battle was going south fast until brave Macbeth fought through the "swarm" of enemy soldiers and disemboweled the traitorous Macdonwald.
There's some gab about Macbeth's great courage in the face of seemingly impossible adversity and the Captain continues his story: after Macbeth spilled Macdonwald's guts all over the ground, the battle flared up again when the "Norwegian Lord" brought new men to the field, but even this didn't daunt Macbeth and Banquo, who just redoubled their efforts.
Oh, but could someone get the Captain a surgeon? He's kind of bleeding all over the place.
The Thane of Ross arrives from another battle, where Macbeth was also kicking serious butt. Sweno, Norway's king, is not allowed to bury his men until he hands over ten thousand dollars to the Scots.
Duncan then proclaims the traitorous Thane of Cawdor will be executed, and Macbeth, responsible for the victory, shall have his title.
Ross is sent to announce the news to Macbeth.
source
http://www.shmoop.com/macbeth/act-1-scene-2-summary.html
Answer:
You only have have of the question posted.
Most likely, Gregor will open the door or someone in his family is going to force the door open. This will reveal Gregor's new form and the reader will get to see how Gregor's family reacts to his sudden transformation. Most likely they will be shocked and afraid at first.
