A dead end corridor has an exit in only one direction. For life safety (for example, to escape during a fire) corridors should have exit access from both directions.
On the NCIDQ Practicum, you can avoid dead end corridors altogether with correct space planning. Per the NCIDQ Building codes:
4.6.2 Dead end corridors MUST NOT exceed 20’-0” [6 m] in length.
The dead end corridor above could be corrected by extending the east wall at the east exit the existing suite (near the 5′-6″ dimension) into the residential suite. The remaining space could be added to the residential suite, and would make a great area for a walk-in closet.