My experience is from housed SLRs. Every flood has been slow rate and catchable, either by looking through the case in an Ikelite housing, or getting squawked at by a moisture alarm. The most I've ever had has been a spoonfull at depth, and that was on a cracked Ikelite housing.
So I've always had time to turn the housing dome-down and get it back to the surface.
The worst flood was actually only a few drops at 60-80', but turned into about a handful in the rinse tank. I've never had the "biblical" flood, where it happens in a few seconds, and fish flop out when you open the housing on the surface.
I'm very anal about o-ring maintenence and keeping the sealing surfaces surgical. Because my limited number of floods have been small amounts and slow-moving, I have avoided the housings that "fit like a glove" and have little or no space available for a bit of water to slosh around without harming the camera body.
All the best, James