That is not really correct based on the available information. Look at the title of the article itself,

The Rock movie plot 'may have inspired MI6 source's Iraqi weapons claim'

The source of Mi6, claimed that Iraq had this. But Mi6 was clearly suspicious, because chemical ammunition are usually not stored in glass containers. This is given just below of the line you quoted,

MI6 accepted this possible flaw to the intelligence, the report adds: “The questions about the use of glass containers for chemical agents and the similarity of the description to those portrayed in The Rock had been recognised by SIS. There were some precedents for the use of glass containers but the points would be pursued when further material became available.”

JFC... What a surreal damned world. That's ludicrous, but if you look at what Trump say or does is doesn't even come close.

Even if true, there's nothing "fun" about the origin story that led to a war killing over a hundred thousands and including some horrible war crimes.

The antidote seemed pretty harsh

There were hostages on the island and if the pearl popped it would infect all of the hostages and possibly caught the wind to disperse over part of SF. Even one would have killed hundreds of people.

If it hit the water it would probably be fine water is very good at diluting stuff.

Japan dumped the radioactive water they had from the meltdown and nothing really bad happened because again large bodies of water are great at diluting stuff.

The only thing I can think of is if there was ground below it could have cracked and possibly got to the hostages.