Shockingly, the plan sort of ... worked? The two men got the poison in his ear, but Mashal's bodyguards saw it and chased them down. The remaining agents fled to the Israeli embassy, which was quickly surrounded by troops. It turned out that squirting poison into a political leader's ear and running away was not as subtle as they'd hoped. The five would-be assassins tried to blend in by falling back on their cover as Canadian tourists, their hopes hanging entirely on people believing that Canadians were so stupid that they would seek shelter in a completely different country's embassy.
And boy howdy, these men were especially not Canadian. They didn't know basic facts about the country, couldn't sing its national anthem, and each wrote "FUCK YOU THIS IS CRAZY" next to pictures of milk in bags. They didn't even know about the Toronto Blue Jays, who had recently won back-to-back World Series. They knew so little about Canada that they might have been trying to invent a fake country and accidentally landed on three syllables that happened to be a real one.
The king of Jordan, dying of cancer at the time, was not amused in the slightest by these -- to be fair, highly amusing -- antics, and put Israel through the wringer. Not only did they have to provide the antidote to cure Mashal, but they were also forced to free a bunch of political prisoners. They failed so hard at assassination that they wound up with a net positive for the living. It was an absolutely humiliating loss, and Benjamin Netanyahu had to fly to Jordan to publicly apologize to Crown Prince Hassan, swearing it would never be repeated. Hassan later said it was one of the most bizarre things he had ever experienced. We're inclined to agree.