[jefftk]

That such incidents don't happen more often in commercial aviation may give us some comfort, but in reality, there have been many attempts by passengers to open an emergency exit door in flight. (Fortunately, it's almost impossible at cruising altitudes).

[tjpnz]

For added context those doors open inward and the pressure differential between the cabin and cruising altitude is such that you would literally have to be superman to do it. When it does happen it's always at relatively low altitudes.