Naik = ke atas
so it could be 'Saya tidak mau naik'?
Yes, it could be "Saya tidak mau naik"
This is very confusing ..if you go down it is turun ke bawah .turun being GO but if you go up it naik ke atas ...naik being GO ... why would they do this to themselves why could we just say ...saya mua pergi naik ..or ..saya mua pergi bawah
In this case 'go' is not beeing as 'naik' or 'turun'. But, you have to use a full phrase. 'Go up' means 'naik' and 'go down' means 'turun'.
That is how the grammar working
What about "Saya tidak mau naik atas"?
For direction, I think we cannot omit the "ke"
For some context, you could just say "saya tidak mau naik"
When your time has come you have no choice
...pasti tidak ada yang naik ke bawa, ya?
well it also can be saya tidak mau ke atas