1/ Yes, this building was weaker, but it's an early indicator of weakness. In the case of a stronger earthquake, who's to say which building is going to survive or not? I tentatively agree that a smaller or similar earthquake won't be a problem. Thus I'm focusing on the 5% scenario of a bigger quake.
2/ The anxiety is totally decoupled from the reality of the situation because our minds are not equipped to evaluate the situation correctly and also that the media/government have incentives to not push mass hysteria. I actually "feel" very chill about it โ on a physical level, my body is perfectly fine with a little shake. Mentally too, I didn't feel stressed about it that much.
3/ The chance of something heavy falling on your head on the 5% scenario is hard to quantify, but it'll depend mainly on your own trust in Thaรฏ authorities to enforce strong buildings. Personally, I put the chance of something harming me in case of a bigger quake to 5% too. That means the ods of being harmed are 0.25%, which looks very little, but to put it in perspective, if you were living at this level of risk for 400 days, you would be dead for sure at the end.
I'm not going far enough to tell the whole story, this is just one variable to take into account for the problem of "should I leave Bangkok a little until things settle down?".
You can make the same kind of estimations about other questions like "should I put a helmet?" "should I put a condom?" etc. I think all choices are fine as long as they're informed and not a "head in the sand" strategy...