Long story short, I was an idiot cyclist thinking I had calculated everything[1], when in fact, I hadn't. Someone in a car going northbound at about 60mph on Sansome had to slam on their brakes to save my life as I crossed from the right bicycle lane to chestnut. I was super lucky they were watching, and their brakes worked, and that they had enough reaction time.
From then on I have never ran stoplights. The problem is that, as they say, the first one is free. You might start out as a cyclist running a simple stop sign on a dead street. But as you get more comfortable, the temptation is to run ever more complex street lights. In my case, I only did it when I didn't see any cars. The problem with intersections like this is there are cars you cannot see.
[1] - Things to calculate:
1. Southeast bound car traffic on Embarcadero.
2. Whether there were southeast bound muni trains on the Embarcadero dividing route.
3. Whether there were northwest bound muni trains on the Embarcadero dividing route.
4. Cars behind you on northeast bound Embarcadero ( I had to cross from the bikelane on the left )
5. Northbound cars on Sansome. This is what I missed.