Where does inductor current go when the RL circuit switch opens?
The answer is found in Ohm's Law, with due notice taken of the amount of energy stored in the magnetic field. An open circuit is effectively an infinite resistance. For the same current to flow through such a resistance, the coil must develop an infinite voltage across itself.

In practice, this doesn't happen, of course. However, the coil does develop a high enough voltage to arc across the switch contacts as they open. This immediately discharges most of the energy in the magnetic field. The remaining energy dissipates rapidly as the magnetic field collapses.