I wouldn’t run round the passenger side either I’d reach over and grab it from the footwell, assuming you have it mounted up near the seat like you should do.
That said, I used to have an extinguisher in my cars before I realised that if the car was on fire I simply didn’t want to be anywhere near it, and that’s why I have insurance. These days I tend to view it that if you’re that worried about a fire, then you either install a properly plumbed in system or you do nothing at all. Safety before all else, and most extinguishers are too small to deal with anything other than the weediest of cigarette smouldering carpet fires, and definitely wouldn’t be any good in a proper fire.
Each to their own though, I’m sure I’ll regret saying that when my car is burning down...