A "jefferies tube" being the name given that that tunnel that James Doohan would be famously inside trying to fix the engines of the Enterprise perpetually in many episodes of the original series of Star Trek..
I can almost hear the cry of "captain, she cannae take anymore" from here... anyway..
according to "wakipedia" (as i call it, in reference to its accuracy...) the "Jefferies tube"
"are narrow tunnels or corridors that provide access to critical starship systems... "
and are a
"reference to Original Series art director Matt Jefferies, the man who designed the original starship Enterprise."
It's a good thing that the surnames of people who invent things aren't that silly... well okay almost all...
So this certainly would seem be a "Jefferies tube" to me...
So what's O'Neil doing inside it? There's certainly no engines to fix here ?
Surely by now you know I am going to say - you will find out beginning of next week?
Well you do now!