Breaking Bad Explosion?!

Question: In the March 2nd episode, Walt chucks a pieace of some mercury chemical onto the ground directly under himself and caused a massive explosion.

My question is how did the people survive being in the same room, or was this just tv show stunt?

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Answers: In the March 2nd episode, Walt chucks a pieace of some mercury chemical onto the ground directly under himself and caused a massive explosion.

My question is how did the people survive being in the same room, or was this just tv show stunt?

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It was a stunt. My question is: why didn't the meth distributor break off a piece of crystal with his knife in front of Walt the same way he did in front of Jesse? Too contrived.

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