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

Q: Heimdall can literally see the whole universe in the Marvel Cinematic Universe. Then why didn't the Asgardians use him to find the location of the Infinity stones and keep them in safety in Odin's Vault? So no evil (like Thanos) can acquire them and use them to wipe half universe. Or they could use them for their welfare.

A: Why didn't the Asgardians aquire the Infinity stones using Heimdall?
****
Q: This question is about "End Times", the twelfth episode of the fourth season of Breaking Bad. When Jesse learned that Brock had been poisoned, he came over to Walt's house to confront him. Walt opened the door holding a gun in his hand. Even though Jesse was obviously mad at Walt, in a couple of minutes Walt left his gun on a couch and walked away, which allowed Jesse to hold Walt at gunpoint using Walt's gun. Was that intentional?

A: Why did Walt leave his gun on the couch when Jesse came to confront him?
****
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?
****