I think that picture in post# 1 is one of my (external ) switches from a while back.
Agreed, not the most elegant, but reliable over time(huge contact area with 5.5mm bullets, pitting is just irrelevant, and very occasional replacement of the esc bullet if becoming slack)
From experience, the most common accidents with f3a-size motor batteries, include (a) shorting of the batterie's positive and negative main leads,and (b) battery fires,most often after a crash.
There are many ways to minimize (a), but making both battery connectors female, and having one male esc connector fixed externally, goes a long way to reducing the risk.
With (b), again from personal experience, and close involvement with other peoples' incidents, pulling apart the external switch, is very likely to halt the fire process.
And believe me, the last thing you want to be doing in a potentially panicky state, is to be fiddling with a canopy release mechanism, followed by delving inside the smoking fus. to disconnect the motor battery internally.