"There was quite a gap between Fisher leaving the cabin and Kirk eventually catching up to him. Fisher could have run a fair way before hiding round the corner and activating the intercom (not fast enough, sadly...)"
"Sadly"? Shall I remind you who the evildoer was (it's written all over your avatar)?
But regardless, there would be another circular corridor adjacent to Janice's cabin.
Yesterday I did some prelimary tests to visualize the Main Sensor-Deflector Engine Room on E-Deck 12 close to the bow of the engineering hull. Janice's cabin "3C 46" would move to the 10 o'clock position (with no need to visualize an ongoing circular corridor moving starboard thanks to "3F 125" in "Charlie X"), but there'd still be a hint of a circular and parallel corridor.
In an ideal world / look I'd prefer a horseshoe corridor arrangement in the engineering hull.
P.S. This yellow door opposite Janice's cabin is irritating me. They didn't change the actual studio set just to have Fisher hit the intercom panel without
the yellow door between the intercom panel and the red alert light?!