To design a safe termination scenario for a burning ITER plasma is a challenge that requires extensive core plasma and divertor modelling. The presented work consists of coupled core/edge/SOL/divertor simulations, performed with the JINTRAC code, studying the Q=10 flat-top phase and exit phase of the ITER 15MA/5.3T DT scenario. The modelling utilizes the recently implemented option to treat deuterium and tritium separately in the SOL/divertor enabling a consistent treatment of deuterium and tritium in the whole plasma volume which is a unique capability of JINTRAC. In addition, these are the first JINTRAC simulations of this scenario to use a first-principle transport model, self consistently model the ECRH power deposition and to include tungsten, keeping track of tungsten sputtering and accumulation. The flat-top simulations demonstrate the possibility of sustaining a steady state fusion Q of 10 using pure deuterium gas puff together with DT mixed pellets which is preferential as it allows a more effective use of tritium. Simulations of the exit phase is set up sequentially starting with a density decay at full current and auxiliary power that demonstrate the possibility to reduce the density safely within a few seconds. Following the density decay, a subsequent auxiliary power ramp down in H-mode is performed with a late H-L transition at low auxiliary power which is preferred for radial stability control. The final ramp-down phase consists of a current ramp-down in L-mode to 3.75MA.