Early in the book it's established that the Intrepid universe is a 'parallel' one created by somebody in (from their point of view) the past. If that's true, however, traveling into the past shouldn't insert them into the Writers' Universe: they should have ended up in the past of the Fictional Universe just as Abernathy, Q'eeng and so forth have done in previous Narrative incidents. Yet time travel worked. This is because the meta-Narrative, the one that Dahl later deduces must exist (using other facts) - the one written by Scalzi and read by you - requires Dahl and his companions to make the continuity jump.
Is it a coincidence that the character who first has an inkling of what's going on is the one played by the head writer? Did he somehow inherit Nick's writing knowledge? Or does Jenkins understand how flimsy their universe is because Nick Weinstein knows how flimsy it is?
Jenkins hides in a back room and develops kludge fixes to the modifications he's made to the ship's computer software, none of which are good enough to last because the computer keeps trying to patch them out as bugs. Weinstein works behind the scenes keeping things running with what turns out to be pretty slipshod work and later gets called out by the deceased crewmembers for it.
Every time the characters meet a cast member who played one of their deceased friends from the show, it turns out they have gotten out of show business and seem to be happier for it. Hester discovers that his actor, Matt Paulson, is in a coma on the verge of death and decides to risk his life to save him. The codas imply that Matt is about to get his life in gear and move on as well.
Andy's degree in religion seems tacked on and a Degree In Useless before you realize his plan to resolve the problem is similar to propagating gods...
In Star Trek: The Original Series science officers wore blue shirts, only engineering and security personnel got the lethal red shirt. Shouldn't Dahl's status as a linguist in an exobiology department make him a blue shirt? It's a sort of subversion of the title in a meta sense for a really meta book. Dahl has to be a Mauve Shirt because if he was an actual Red Shirt, like Davis, then he'd die before we even got a story.
The title may refer to the point in the novel where the actor playing Dahl Lampshades this Trope, calling his own character a Red Shirt in the process. The confused reaction from Dahl and the other characters who heard the comment suggested to me that they weren't literally wearing Red Shirts, despite the book's cover suggesting otherwise. That, or everyone on the Intrepid wore red uniforms, with rank/department being marked out by some other form of insignia, so they didn't understand why their wearing red shirts was in any way linked to their being singled out for punishment. As for the fact that Dahl and co. are actually Mauve Shirts (possibly wearing Blue Shirts) - not as many people are familiar with this phrase, whereas most people even passingly familiar with Star Trek and its influence on popular culture know what a Red Shirt is, so that's the phrase that's used in the novel. Of course, and most importantly, Red Shirts makes a much cooler (and more immediately understandable/culturally relevant) title than Mauve Shirts or Blue Shirts.
It's also worth noting that the red shirt thing has always been more Common Knowledge than actual Trek practice. Not a single Red Shirt dies for the first three or four episodes of the show (the first on-screen deaths were a Gold Shirt in "Where No Man Has Gone Before" and a Blue Shirt (who lost thewill to live) in "The Naked Time." Also, while Red Shirt deaths are common in the original show, they are also the least likely to die when the distribution of shirt colors is factored in (more Red Shirts die on screen because there are more Red Shirts on the crew). To make it more confusing, as soon as The Next Generation premiered, they had swapped the uniform colors around so that the command staff mostly wore Red Shirts and it was the Security and Engineering guys who wore Gold and were subjected to attacks by angry aliens and difficult engineering challenges.
