BUG: Problem in the cellar with Blacksmith

I went down into the cellar to help him with his task in new tristam. However when entering the basement and i destroyed the door , my latency jumped up to 3500 and it took forever to kill the first wave of undeads. Took 20 seconds for them to die. After that i walked to his wife and nothgin happens. i tried leaving the basement but i cannot exit. I cannot even leave or quit the game, except alt tabbing out and killing the process.

I have been encountering this huge latency issue for the past 30 minutes. Game was running fine all day until then.