It’s 18k feet of rock they have drilled through. You just close the upper part, drill down next to it and insert nuke. Or if that freaks people out, dump in conventional explosives. They could at least test the idea on a smaller scale somewhere else. We have everything we need to test it and see if it would work. Soviets have done similar in the past.
If while they are pumping mud into the well the oil flow stops, why don’t they continue doing that until another solution is ready? Seems to make sense.