imagine a nitrous B20B.

stock RPM limit.

combustion goes bang, rod goes down.

where are the other three rods?

there is another piston/rod going down too, but it is being pulled down by the crank with no force on top.... (NB - this rod and piston has inertia)

imagine what is happening to the rod bolts on that rod?

are the forces on those rod bolts going to be the same if the forces on the other piston are higher due to the higher combustion pressure?