Does 10 degrees of flap have any real effect on braking efficacy? Assuming you're braking heavily surely by the time you've reached the flap lever and got it up you wouldn't be going fast enough for it to make the slightest difference? Not in a C150 or similiar, I'd imagine.
I think that in the time it takes for me to clean up the 10 degrees of flap, I could have leaned the mixture, closed the throttle, fuel cock off, masters off etc etc.
Pressurised fuel + fire is something I want to be around for the least time possible.