Once the shields and hull were penetrated, whole rooms of the ship would be destroyed at once. It doesn't make sense that exploding consoles from a hit kills someone at one console without hurting the person next to him. It wouldn't be as dramatic, but a hit would either destroy the bridge or not. I would not kill the navigator and leave everyone else unscathed.
I would think it was take many many hits to get through the bridge.
As far as consoles full of plasma blowing up in your face. I'd say thats believable. Think about it like this. During a thunder storm you take a near hit from lighting. Is everything in your house destroyed? Not likely not. Just a few things. Same thing.
Lets say the starboard power coupling gets hit. (it's made of glass) Depending on whats going through it at the time depends on what hapless redshirt is killed.
See, super easy StarTrek Logic.