TedStixon

Answer: In Season 9, Episode 20 of "Mythbusters," Adam and Jamie tested whether a person could survive a "toilet bomb" (recreating a Lethal Weapon 2 scene) by jumping into a cast iron bathtub and being covered with a bomb blanket. They used 1 kg of C-4 explosives that created a blast with a peak lethal pressure of 180 psi outside the tub. The pressure inside the tub was recorded as a survivable 8 psi, though with probable hearing damage. From what I read, a grenade has a much lesser psi force than what the C-4 explosion produced. Depending on the circumstances, it seems plausible that a person could survive the force and shrapnel while inside the tub.

raywest ★

Answer: It's plausible but highly unlikely. Assuming it's an old metal bathtub (which seems to be the case), it's possible it might have deflected enough of the percussive shock and shrapnel to save him, but unlikely that it'd stop everything. It's one of those things where it probably wouldn't work 90% of the time... but there's that 1 out of 10 chance it could possibly work if he got really lucky and no big pieces of shrapnel came his way. (Plus, stranger things have happened in real life).

TedStixon