It wouldn't take much warming to belch a large volume of methane gas to the surface. You don't want to be nearby when that happens.
You especially wouldn't want to be in a ship or platform floating on the surface. The methane hydrate bubbles would change the density of sea water below and cause the loss of bouyancy.
"You don't want to be nearby when that happens"
Until they drilled the wells on the Long Beach and Seal Beach platforms their was large volumes of oil and gas boiling to the surface on the horseshoe kelp 7 miles off Long Beach harbor.
Same thing in the Santa Barbara Channel.
Before the platforms and drilling there was a giant oil slick from the Channel Islands to Mexico and all the beaches were covered with oil and tar.