That's interesting ... I thought the tower staircase was added when the bldg was remodeled for TV; but I guess from this the TV addition would have been over on the Space Needle side only. Reminds me that all the TV facilities had their own cafeterias ... KIRO was first to drop theirs' and go to vending machines. KING had Hazel for a long time running the kitchen ... was great to go in and have a pancake w. cup of coffee and hang out to see who wandered by (not sure but they may still have a working cafeteria...and would be the only ones who still do). As I recall KOMO didn't have TV until after 1950 ... there was a freeze after KING went on in 1948 giving them at least two years running solo as only TV station in town before other licenses issued to 4, 7, 9, 11 & 13...
As I remember it you would walk in ... switch board was on the right...radio studios straight ahead ... and admin upstairs. When TV was added, they put in a studio just off the lobby (to the left) and that was where "Capt. Puget" aired...then news and production studios near the center of the bldg. When radio moved out (over to Tower Bldg), eventually news moved into the old radio space (they had been in the newer part of the bldg near where the center of Fisher Plaza open court now stands). Also just prior to that they pretty much sealed off the bldg and moved reception up next to the street so you had to get buzzed in and could no longer just walk in. Sign of the times ... as that was shortly after KING had people drive into their lobby (twice no less) ... the reason for the statue in front of the door. Now you can't even walk into KING lobby either...have to get buzzed in. KIRO had a huge lobby with large pic's of CBS stars + local news anchors; and cut their lobby down to about 1/3 when their security went in.
Was kind of a nicer deal when a TV facility in this town was a huge deal. Heck...now you've got KSTW with most offices next to CBS radio; and a huge but empty operations center down at Renton which is essentially useless because station operates out of SFO and doesn't even have a studio down in Renton.