How to determine current direction against a parallel current source? basic question
The directions you pick when defining the current direction for the purpose of the equations are arbitrary.  If after analysis the current is found to go the other way, the value will simply be negative.

There is no problem with that.  Pick a direction to start with, and let the math work out how it works out.

Put another way, -2 A right to left is the same as +2 A left to right.