That was close. The rocket impact in the Polish border village of Przewodów showed how little it takes to explode the proverbial powder keg. And what did Ukrainian President Volodymyr Zelenskyy do? He lit with matches. “This is a Russian missile attack on collective security,” he stormed immediately after the first reports.

With all understanding: A president has to keep a cool head in such a situation. Thinking instead of tweeting is the motto. Because scaremongering helps absolutely no one here – not even Ukraine.

In the meantime, tempers have calmed down, the world has apparently (for the time being) gotten away with a black eye. “Nothing, absolutely nothing indicates that it was a deliberate attack on Poland,” said Poland’s President Andrzej Duda on Wednesday. Like US President Joe Biden, NATO also concluded that the missile was “most likely” a stray Ukrainian anti-aircraft missile. The only thing you know for sure is that you don’t know anything for sure.

Only in Kyiv do people continue to want to know more than everyone else. “I have no doubt that it is not our missile,” Zelenskyy said on Ukrainian television on Wednesday. Instead of taking a deep breath and at least contributing to the de-escalation at the second attempt, the President acted defiant. So far he has seen no evidence that it was a Ukrainian missile, he mocked and demanded access to the site of the explosion. How you can be so sure in Kyiv, even though you weren’t there yourself, remains a mystery. Only on Thursday did Selenskyj row a step back: “I don’t know what happened. We don’t know for sure. The whole world doesn’t know,” said the head of state. A late insight, but still.

The fact that Zelenskyj persisted in his position two days later undermines his credibility. Right now it’s not about assumptions, it’s about facts. With all sympathy for Ukraine: Russia (although the market leader) does not have a monopoly on disinformation. Although in the case of Zelenskyj one would not necessarily suspect intention, but rather excessive emotionality.

Now, at the state level, even the subjunctive can have serious consequences. But there was no talk of would, could, in the presidential tweets. Zelenskyy not only expressed doubts that the rocket was fired from Ukraine. For too long he pretended it was a Russian missile.

Every president must be aware of the repercussions of his allegations, especially a president whose nation has been forced into a war. It is thanks to the level-headedness of Poland and the NATO members that the situation did not escalate in the first few hours.

It’s hard to blame Selenskyj for assuming the worst imaginable after almost nine months of war. For too long the West, not least Germany, had been the sad, head-shaking onlooker while the Russian invaders murdered their neighbors. The calls for help from Kyiv had gone unanswered for too long, too many empty words and not enough real action. Time and time again, Kyiv has sworn to its allies in the West that the attack was also aimed at them, that Putin’s campaign was an attack on everyone’s security. Zelenskyj’s hasty reaction after the rocket hit Poland was nothing other than: See, I told you so!

Of course, it could still turn out in the end that the rocket was of Russian origin – after all, the investigations are still ongoing. Until then, though, given the nightmare that could become a reality, the mantra has to be: keep calm. This applies to all sides.