There's no "fall back" logic supported in OldRoutine. In our next routine revamp update, that should be possible, but as simple as it sounds, it often causes more issues and slowdowns than people really want. Basically, it means moving back into a position that the routine might not be able to target the mob anymore, then it moves forward again to fight the mob, but then goes back. Without lure mecahnics as well, it can pose an issue in a lot of tilesets, and is a concept that is only so useful due to mob speeds and teleport skills now. There's no one general way to make it better, so that's why OldRoutine is just a face tank routine and relies on characters having good gear and DPS.