Your guess was as good as mine, he seem to hand the tanker groceries at one point, seems to gesture them to go back to the square, and has what looks like a full on convo with them.
Wowsers, I never knew the tanks were there as an honour guard to politely support the protestors. I suppose a lesser country would see sending tanks against the people as pure cowardice, but that time tanks were sent to show support to the people protesting against them! Very upright and cool!