@Ying, first of all sorry to hear that your wife had this accident. It sounded like she was/is OK physically, which is the most important thing. Damage-wise, $4K isn't a small amount but, for a family who lives in the Bay Area and could afford 4 Teslas, I'm guessing that you guys will probably be just fine.
I'm wondering though, about what exactly are you guys trying to achieve here. Data in the logs doesn't lie. Well, I suppose it could be erroneously instrumented, but the data is the data, and in this case based on it Tesla says the following (quoting your wife's initial post):
Tesla said I was on the pedal for a second long, I applied pedal from 0-18%, and quickly applied the brake.
So, logically speaking, one of the following is true:
1. Tesla mis-instrumented things so that data captured in the car's log isn't accurate
2. The data is accurate but Tesla misinterpreted it when they presented their findings to your wife
3. Tesla flat-out made stuff up and lied to your wife (i.e. data actually says there was no application of the throttle)
4. Your wife actually did what the log says happened
5. Something else caused what the log says happened
Which of the above are you trying to prove?
From the sound of it, it's one of the first three. But if you fundamentally distrust Tesla to such extent, your continued and significant investment in them is very contradictory. And I don't know how suing them (something that I believe I read your wife is pursuing) regardless of the outcome is going to suddenly increase your trust factor in them.