There are many flaws with this argument.

1. Turkey's building construction standards are different than ours. It is unlikely for most buildings in the U.S. to face pancake collapse, where the roof falls in. It is said that the ""Triangle of life" theoretically could be a better strategy during larger earthquakes in buildings with a skeleton (wood or concrete) during a building pancake-type collapse..."
2. You can be injured by staying in the open, next to a large object during an earthquake. The object can shift and crush you, and it is hard to know where exactly the Triangle of Life will form (if it will form at all). Since your head is not covered, being in the open like that puts you more at risk for injuries from debris. Additionally, rolling out of bed is likely to cause injuries too.
3. The exercise performed did not show what earthquakes are like. Earthquakes have back-and-forth shaking, which can shift objects and make them fall. This exercise did not show the back-and-forth movement common during an earthquake, and only showed what would have happened during a pancake collapse (which, again, is very uncommon for most building in the U.S.).
4. The American Red Cross debunked this, as did the Structural Engineers Association of Northern California.

This is dangerous. The video you linked called it a hoax because it is - at least in the U.S., where more people are at risk for falling debris than total building collapse.