Soviet tank crew survival.

[Marcello]

"RPG hit side hull at place where was only a few cm protection.

Side hull is a rolled steel plate presumably in the 8cm range.BUT in addition to that there is the side skirt.The round exploded against that.That means a non trivial standoff between where the warhead explodes and the side hull plate.That would help to dissipate the jet, ensuring that the side hull plate would not be hit at full force.

"It got though whole hull side and exit at other side... It has definitly enough power"

It made a small dent on the opposite side, but it did not penetrate that plate.It was a small, albeit surprisingly well focused for an RPG, HEAT jet.It could not cause the overpressure event you would get from a M829A1 crossing a tank side by side or from a TOW-2.The warhead was simply not that powerful in first place and it had to throught the side hull and the airgap before getting inside.
Yes an HEAT jet moves very fast but you have to consider the amount of stuff which is moving.At that point there was probably not enough of it to do more than damaging some systems in its direct path.