You don't need floats to remain [basically] on the surface for 7 minutes. Cargo compartments, fuel cells, and other areas can entrap a lot of bouyancy. This can keep a helo on the surface for closer to an hour.
This would not require any float inflation.
Inadvertant reduction of airspeed below T/L [at night] will also feel very much like a loss of power due to late visual cues of what is happening.
Basically what I'm saying is that the available information here tells us next to nothing.