Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

Q: I was trying to understand how the main computer at the end of the 3rd part of the Matrix trilogy could kill agent Smith, at the point of programming ( both agent Smith and Neo were programs in that space), when Agent Smith turned Neo into his copy.  How did the main computer realize that? I mean, there were totally a lot of copies of agent Smith, and it could be links that were linking to the main object (real Agent Smith). Or maybe they were independent copies?  They absolutely weren't pointers, because insurance from 1 example hadn't influence on the original.  So how did the computer accomplish this?

A: How did they kill Agent Smith?
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Q: As we all know, the most exciting part of seeing a movie is the trailers of upcoming movies before the actual film (note, this is coming from an American point of view, I am uncertain if this occurs in theatres everywhere).  However, there doesn't seem to be much of a forethought given to what trailers are shown, besides making sure big movie trailers are shown before other big movies. For instance, the idea of seeing a Dark Knight Rises trailer before Avengers (two different production companies, let alone two rival comic book companies) doesn't seem to make much sense to me.  Is there a strict guideline trailers are released controlled by the MPAA or do the theatres have free run of what to show?

A: What factors go into determining what trailers are played before movies?
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Q: During the first episode of Season 3 of The Walking Dead, I noticed the group is now very cavalier about taking down walkers:    This is a staunch contrast from the first season when they covered themselves in walker parts to get through Atlanta. I don't have that scene handy but, in my mind, it seems like they were very cautious in how they covered themselves (e.g. seemed like they were wearing HAZMAT suits).  I understand that, as time passes, the characters learn more Walker do's and don'ts; but I was under the impression if Walker blood got in their system, they would turn.  Is this true or have I imagined this rule?

A:
As of S03E01, does walker blood have an effect on open orifices/wounds?
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