In Lost Dasmond talks to his future father in law and tells him the following:
What makes you think that I would run away.
I was wondering what tense it was and why 'would' not 'will'?
Would here is an example of what is traditionally called the Second Conditional, and indicates the likely outcome of a hypothetical situation. I don't know Lost, but I'm assuming that Dasmond is confined in some way and saying something like:
contains no hypothetical aspect. Dasmond's interlocutor thinks that Dasmond is going to run away and Dasmond wants to know why.
On further reflection, it is indeed possible to construe the sentence:
as hypothetical, using the First Conditional.
So the usual principles apply when choosing the conditional 1 over the conditional 2. Namely that the conditional 2 implies that the possibility (in this case) of escaping confinement is more remote.
To answer this sensibly we need to know what went before. It may be as Shoe says, but there’s another way of looking at it, and that’s as reported speech. The person addressed says ‘I think you will run away’. Although the speaker responds with a question, he is still reporting what the first speaker said. When speech is reported, the time indicated by the verb is shifted backwards. In cases such as this, ‘would’ can be seen as the past tense of ‘will’, and that may be why it’s used here.