A simple incident during the construction

Recently, I heard an accident from my friend who experienced during the floor tile work in his apartment. Tiles were purchased and brought to the apartment. The marble tiles (about 10' x 6') were kept in an inclined position in the corridor outside the apartment. The corridor is about 4' width. Next day, when he went to construction site, one of the worker commented that the tiles are having vertical straightline cracks and appear to be joined with white cement.
To check the condition, the person in-charge for laying the tiles was called. Both my friend and the worker pulled one tile to vertical position and checked for cracks. To the dismay of my friend, there were such vertical lines as if joined by white cement. Then, 2nd tile also was brought to vertical position and then the third. While checking the third, by holding the tiles in vertical position with my friend on one side and the worker on the other side, slowly the tiles started moving towards the worker's side as the center of gravity (C.G) shifted. This could not be seen initially, but shortly both understood something is wrong and tried to push the tiles to the wall without success. The tiles were now heavy and beyond the capacity of the both persons. Both shouted for help.
Immediately, workers in the ground floor rushed and with great difficulty, the tiles could be put back into position. By that time, the worker had chest congestion because of the weight of marble tiles on him. Immediately, he was rushed to the hospital and the person was alright in a day.
The above accident is unimaginable for ordinary folks like us. The fact that the experienced construction worker also did not caution before examination shows that we have to learn a lot.

Later, on enquiry, the supplier informed my friend that they are not cracks but lines which come during polishing and that he will not spoil his reputation by supplying damaged tiles. He offered to replace the tiles of much superior quality and premium brand, even if one single tile shows cracks.

Similar to the above incident, I remember, few years ago, when my child (about two years old at that time) climbed over the refrigerator racks to take some fruits, the refrigerator started falling towards the floor.
Fortunately, I was next to the refrigerator and immediately could hold and stop the fall of the unit. Otherwise, my child could have got injured under the falling refrigerator.
Same is the case, when we go up the portable ladders and try to access by over reaching. Then also, ladder can fall on the side because of shifting of C.G.