Algorithm for "short-circuit" current draw
You've got it basically right.

The only complication in the real world is that neither of those resistances are static. Both the internal resistance of the battery and ohmic resistance of the wire will increase as a function of temperature. And if you short out a battery, you're likely to get a large increase in temperature in both components.

Lithium batteries have this neat feature where if you short the terminals together, it activates the nearest fire truck in your town.