Before being ushered out of the room where Donald Trump and Xi Jinping were to dig in to a menu of chewy trade negotiations, the reporters gathered there launched a deafening barrage of questions at the US president.
Stony-faced and shoulders hunched, he glowered back at them in silence. Xi, on the other hand, chuckled heartily at the spectacle, loud volleys of questions from reporters not being a staple of his presidency.
The moment spoke volumes to body language experts Rebecca Klein and Keith Scott, who analysed the footage from Buenos Aires and concluded it suggested insecurity on the part of Trump and relaxed confidence in his Chinese counterpart.
The episode immediately put Trump on the defensive, said Scott, one half of the husband-and-wife communications team from Baltimore. "Trump can't stand the press so he's not comfortable at all - He wants to have a total sense of power".
Leading up to the high-stakes dinner, much was made of Xi's weakened position. His country's economic growth was slowing under the shadow of the months-long trade war, but his body language and that of his delegates presented an image of quiet confidence, according to Klein.
According to preliminary reports, that confidence appears to have been well-founded.
Following the meeting, China's foreign minister Wang Yi announced that both sides had agreed not to levy further tariffs and to halt any raises in existing tariffs.
Trump had previously said it was "highly unlikely" he would suspend the increase in tariffs on US$200 billion of Chinese imports that had been expected to come into force on January 1 - a critical point for the Chinese side.
"Many of them have their hands visible", Klein said of the nine-strong Chinese delegation, a number of whom had their hands clasped and placed on show atop the dining table.
"That shows more of an openness. On the US side you don't see that as much".
While Trump leaned forward, his shoulders slumped, his delegation, which included several of the administration's most hawkish officials when it comes to trade and China, sat back in their chairs, hands hidden below the table.
"It almost feels like they're thinking: 'Am I going to be the next one to leave the White House?' They all look pretty freaked out," said Scott.
Xi's reaction to Trump's opening remarks, in which the US president expressed confidence that outcome would benefit both countries, was also noteworthy, according to Klein.
"The way he nods in a measured way, it does not look forced," she said. "It looks calm and comfortable and confident."
Xi let his eyes wander up and down the row of American officials as Trump was talking, rather than making sustained eye contact with the US President.
Scott said that did not suggest an indifference towards Trump, but showed that he was "taking in the different personalities" of those involved in the discussion and "looking at the whole situation from a broader viewpoint".
Trump, on the other hand, appeared far more "laser focused", he said, as if he were "bracing for a fight".
"When it's Trump's turn to do the listening, he doesn't emote much. He nods only rarely", said Klein. "He's not there to be with everybody at the table".
The non-verbal signs on display were a form of "perception management" said Joe Navarro, a body language expert and author of The Dictionary of Body Language. "Trump and his team want to look tough and Xi and his team want to look resolute".
"This is a performance being played out both at each other and for international as well as national consumption."