This is completely off topic for my regular blog, but it took me almost an hour to find any posts online that would help me overcome this bug and I feel like I should share the solution and post on how to walk around the problem.
My fireman Sim is at the top of the fireman career path. When he gets to a large house fire, he manages to put out all the fires on the windows and in the yard, but he is unable to enter the house to save the panicking sims. All the walls of the house are raised and his only option when clicking on the front door (after breaking it down) is to visit the household. The household won’t respond due to panicking because of the fire. He cannot enter the house to save the sims.
Make your fireman/woman leave the lot of the large house fire and go to the neighbours lot. Then make your sim return to the lot containing the large house fire. (S)he should now be able to break down the door and enter the house.
This worked for me. I hope that it works for anyone reading this.