It’s not. What’s happened here is this dude is revving the engine while the car isn’t moving. The car isn’t designed to do that. That’s a problem on these type of rear engine cars because they have everything wrapped up in a small space. To be specific, the exhaust produces a lot of heat, see the fire coming out the exhaust pipe he’s using to barbecue? Constant fire in metal piping makes them really hot. The exhaust is normally cooled by airflow from driving. Take away that airflow and now he has an over heating exhaust. Combine an over heating exhaust with components like cooling hoses and you have a recipe for a pipe to either lose some of its strength and burst, or melt and develop a hole for the engine coolant to escape.

On the other hand, this is a short video. For all we know, he could’ve started the car 30 seconds ago and this is the result of a failed hose clamp. Either way, this doesn’t appear to be anything major.