Assuming this has been created so far with a Corridor... stop the corridor in the area of the intersection and model the blank area with Featurelines, adding them to the Corridor Surface.
Hello @Marielen_ ,
Just checking to see if your problem has been solved. Have you tried the suggestions from above and did any of them work? If yes, please click on the "Accept as Solution" button in their reply so this helps other users in the community find the solution too. Thanks!