after your last post and re-reading the first post it sounds to me like the reverse mixer is engaging after 3 seconds of throttle, rather than 3 seconds of brake.
it sounds like you need to reverse the servo direction on channel 3
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It's "Dr. _paralyzed_" actually. Not like with a PhD, but Doctor like in Dr. Pepper.
you could also just run a y cable and use the esc and brake on ch2 and use the 3rd channel independently (without a mixer, that's a kitchen appliance) to shift the reverse servo
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It's "Dr. _paralyzed_" actually. Not like with a PhD, but Doctor like in Dr. Pepper.