The modifier ālme is related to the noun jālme, which means ‘ford, crossing’. So the central definition of ālme denotes crossing something long and narrow from one side to the other, very much like ‘across’. ālme has expanded its range to include crossing any area, from one side of the area to the other side of the area. One border to the area must also be crossed. So one can start inside the area (at the edge, but inside) and cross to outside the area, or from outside the area to the opposite inside edge of the area, or from outside the area through the area and across the next border to outside the area again.
rā NP ālme is across NP and rū NP ālme is from across NP.
rājālme is rā NP ālme without a specified location, and so means ‘across’.
Likewise rūjālme is rū NP ālme without a specified location, and so means ‘from across’.
ñi jahāþa rā jatōna ālme tō-kēñ;
Why did the “chicken” cross the road?
tō ñi rājakiē;
To get to the other side.