Once you are being arrested, you are no longer a bystander, so you may continue filming.
I understand your fear of the chilling effect this may have, but I would guess there will be just as many people who now feel empowered to say “This is my right. I’m 8 ft away.”
> B. NOTWITHSTANDING SUBSECTION A OF THIS SECTION, A PERSON WHO IS
22 THE SUBJECT OF POLICE CONTACT MAY RECORD THE ENCOUNTER IF THE PERSON IS
23 NOT INTERFERING WITH LAWFUL POLICE ACTIONS,
The basis of being subject to this law is that you are interfering with police actions, and lawfulness can only be determined by the courts after the fact.
I don't think it's a foregone conclusion that you would be in your legal right to record the police if you were being arrested for violation of this law, and likely it's something that would need to be tested fairly considerably in court before a definite interpretation was set.
This is a really badly designed/defined law, and I would not rely on the guarantees of the law as being subject to it means it's already been determined you're interfering with police action.
Let's say you were 4m away and got arrested anyways. The officer stopped you from filming and it deterred others to start filming too.
Even if the charges get dropped later on (which they might not), the police already succeeded in stopping you from filming.