 Because of this, Derek has lost his last-chance of reconciling with his ex-wife and their children.Seeking retribution, Derek steals a gun from Gary's shop and ends up instigating a siege in The Rovers while trying to find Gary.When Gary attempts to call his bluff, Derek fires the gun to prove his intent on killing Gary - unknowingly shooting Michelle's estranged husband, Robert Preston (Tristan Gemmill), in the process.