Re: To happen = to fall ?
The verb 'happen, occur, take place' is tapahtua (related to tapa, "way of doing"?) or sattua (which also means 'hurt' as in 'It hurts'). As for related words, I recognize the idea of walking/going/moving forward/being in movement:
Kaikki kävi parhain päin. Everything turned out well. (käydä = (roughly) walk)
Asiat kulkevat omaa rataansa. The things follow their own course. (= you cannot affect things too much, just as the Earth follows its 'path' through space with little interference; kulkea = (roughly) move, progress forward)
Could the expressions How's it going? (Miten menee?) and The exam went well. (Koe meni hyvin.) be related, by the way? There's something similar in them, the way I see it. Happening (/result) is connected to moving. Could you use uitvallen to describe an exam?
That which caterpillars call the end of the world, we call the butterfly. Sitä, mitä toukka kutsuu maailmanlopuksi, me kutsumme perhoseksi.