Here's an English language press release (.pdf) of the Eureka4 holster.
The translation from Spanish to English leaves a lot to be desired but it is understandable.
"ventana de expulsion" = literally "point of ejection (gun)" which I am assuming means the gun's ejection port.
I'm gathering that the gun is placed and carried in the holster in condition three and the act of pushing down on the gun to release the holster's retention mechanism jacks a round into the chamber.
Side note: The young lady in the first video is in NO danger of drowning.

