One of Mildred's first lines is to ask for a Fourth Wall in their parlor, showing her desire to literally and figuratively surround herself in fantasy to shut out the real world.
Considering the government has no problem burning people's homes just because they read books, it is very well possible Clarisse was murdered by the government for being a free thinker. Her family is said to have "moved away", but what if they were also subjected to terrible fate at the hands of the government?
The narration almost treats this as an afterthought, but aftter Millie has her stomach pumped, she also has her blood replaced. There's a throwaway line that "her blood was now another person's" - not "donated by other people", one other person's. Who's therefore now dead. Either way you can take this - did they murder someone for it, or has this society where admittedly death is cheap found a way for all those dead to donate their blood along with other organs - just consider how often something like this happens in the book's setting...
another possibility would be that they then wash the blood they took from Millie of the drugs, and give the next person who needs the same operation the now clean blood they have from Millie, replacing theirs ... and so on.
Why, when everyone else ignored her, did Montag listen to Clarisse? Clarisse says that he's the only one that's listened to her... so why Montag?
Law of Averages, mostly. No indoctrination program sticks 100%. Clarisse herself is an example of that. Montag just happened to be the guy who listened...and of course, he's the one the book follows, because he's one of the odd ducks. Montag was also incredibly frustrated and bored with his life, so he was ripe to listen to anyone who was just as fed up as he was.
It's also worth noting that at first, Montag didn't listen. He just took for some dumb kid mouthing off about things she didn't know anything about (like talking about firemen in the far past putting out fires). It's only after he has to listen to her rambling and raving that he realises she actually has a point. If he'd just turned and walked away at the very beginning, he likely never would have changed at all
People's preference for entertainment over politics and current issues may be part of a cyclical effect: the less power ordinary people feel they have over shaping their world, the more likely they are to turn to entertainment because that is the one arena where they still can have power and control over their own lives.
One for the tie in game: After Montag fights his way into the library and frees Clarisse, the two grab some microcassettes containing an archive of all the books that the New York library system had. They break into an office, upload the contents, but are trapped and die horribly by the Firemen, immortalized as martyrs by the Underground. However, there's a last "Leave Your Quest" Test proposed by Clarisse after getting the tapes, but before the fatal upload. Taking it means you abandon the Underground, and get a Nonstandard Game Over. However, why isn't grabbing the tapes, hauling ass, and uploading them in the safety of an Underground safe house not on the table?
