Here's an excerpt from the Doomsday article by Terrence Aym:

"If the methane bubble—a bubble that could be as big as 20 miles wide—erupts with titanic force from the seabed into the Gulf, every ship, drilling rig and structure within the region of the bubble will immediately sink. All the workers, engineers, Coast Guard personnel and marine biologists participating in the salvage operation will die instantly."

"Next, the ocean bottom will collapse, instantaneously displacing up to a trillion cubic feet of water or more and creating a towering supersonic tsunami annihilating everything along the coast and well inland. Like a thermonuclear blast, a high pressure atmospheric wave could precede the tidal wave flattening everything in its path before the water arrives."

As alarming and hopeless as this all is, I'm not really sure who Mr. Terrence Aym is and what his credentials are, so don't necessarily trust what he has to say in this article. I can't find out much about him. The information could be valid, but it could also be philosophically-motivated and overly-biased, so read with a grain-of-salt.