Learn English – “stray shower” mean

I see where this is going roughly means I know what is going to happen. It is used to indicate that you can predict how something will change, where it is headed, or the outcome of something. Of course, your prediction doesn't have to be right.

In the video, the lady is saying that she knows what will happen. However, we can't really know what her prediction is because she doesn't say it out loud. Maybe she predicts that her logical answer ("20") is correct because respondents are expected to answer "5". Maybe she predicts that her logical answer will be wrong because it's a trick. Maybe she realized that the correct answer is "no time at all because it's already built". We can't really say.

As for another example, imagine a superhero and a supervillain. The hero faces a dilemma: save A or save B. A is on one side of the bridge and B is on the other. There is only enough time to save one, according to the the villain. But you might say I see where this is going. The hero will do X, Y, and Z in order to save A and B. In other words, you predict that the hero will be able to save A and B despite what the villain said.

Sydney's answer is right in that "bless you" is what you say in English after someone sneezes, but I don't think it addresses why it was said in this context.

In American English at least, it's a pretty common joke to say "bless you" after someone says a weird word, like bouillabaisse. The word doesn't have to sound anything like a sneeze, it just needs to be uncommon or have a weird pronunciation.

Think of the motivation for it like, "What you just said sounds like gibberish," as if the person sneezed.

I personally haven't heard it used too much outside of books and film and other media, but that doesn't mean you can't use it in conversation.