Yep, the complete width of your (moving) bot while the wave iterates over your bot. So it can be close to 60 pixels for a bot on full speed and a full power bullet. (Botwidth 36 + 3 ticks of 8 wide). How you record it is up to you, bins or angles. Next to that, getting closer to an enemy makes your botwidth relatively larger compared to the Maximum Escape Angle you have.
What an interesting observation! It looks like there are benefits when wave crossed with 0 lateral velocity, even if it reduce MEA.
My bots logic completely ignored the fact that bot might hide in its own shadow. No the question how to program it efficiently, without doing a full blown game emulator.
However, I discovered that it's not worth to stop to decrease botwidth/mea rather than try my best to maximise mea.
Maybe it's simply because our enemy is not firing randomly ;)