Looking at the script again, the lead-up to boarding Space Station Regula I is actually made a little creepier:
109 INT. BRIDGE - ENTERPRISE 109
Battle damage, some repaired, some not. The bridge is
filled with tension, all hands at station.
SULU (V.O.)
KIRK
UHURA
110 INT. SPACE STATION REGULAR I - CAROL'S LAB - ON SCREEN 110
As before, Uhura's image, imploring a response.
UHURA
During this, CAMERA HAS PANNED CLOSE AMONG the techni-
cal clutter. Then suddenly. SOUND -- eerie, frightening.
Our ears cannot place it... and before we can, it is gone
a warning.
Battle damage, some repaired, some not. The bridge is
filled with tension, all hands at station.
SULU (V.O.)
Approaching Regula and Space Lab
Regula I.
Regula I.
KIRK
Try again.
UHURA
Space Station Regular I, this is
Starship Enterprise. Come in, please...
Starship Enterprise. Come in, please...
110 INT. SPACE STATION REGULAR I - CAROL'S LAB - ON SCREEN 110
As before, Uhura's image, imploring a response.
UHURA
I say again. Space Station Regular.
This is Starship Enterprise. Please
respond. Please respond.
This is Starship Enterprise. Please
respond. Please respond.
During this, CAMERA HAS PANNED CLOSE AMONG the techni-
cal clutter. Then suddenly. SOUND -- eerie, frightening.
Our ears cannot place it... and before we can, it is gone
a warning.