panic
Explanation
The comic shows someone shouting "Everyone! Fire! Go panic! Make sure to panic! Paniiiiiiiiic!" while a building is clearly on fire. In the next panel, people are screaming "AAAA!" in panic while one person calmly says "Nope" and walks away unbothered.
The caption at the bottom reads: "Finding: you can't get people to calmly exit a building via reverse psychology."
The joke is about a misguided attempt to apply reverse psychology to an emergency situation. The idea behind reverse psychology is that if you tell people to do something, they'll instinctively want to do the opposite. So the person reasons that if they tell everyone TO panic, people will contrarily remain calm and exit in an orderly fashion.
The experiment fails spectacularly. Almost everyone panics exactly as instructed, because when there's an actual fire, the natural instinct to panic overwhelms any contrarian impulse. Only one person responds with the hoped-for reverse psychology effect by calmly refusing to panic -- which is itself dangerous, since there's a real fire and they should be evacuating.
The humor lies in the absurdity of trying to apply a simple psychological trick to a life-threatening emergency, and in the format of presenting this as a scientific "finding," as though someone actually ran this as an experiment. It also pokes fun at the popular but overly simplistic notion of reverse psychology, suggesting that it doesn't work when the stimulus (a raging fire) is strong enough to override social defiance.