Guest Stars Dominic MacHale as Sergeant Healy Demi Isaac Oviawe as Linda Walsh Jennifer Barry as Siobhan Walsh P.J. Gallagher as Principal Barry Walsh Orla Fitzgerald as Orla Walsh Shane Casey as Billy Murphy Ciaran Bermingham as Garda Quinn Joy Buckle as News Reporter Conor Devlin O'Mahony as Billy Murphy's Brother Liam Devlin O'Mahony as Young Billy Murphy Harley Devlin as Billy Murphy's Mam Ross Browne as Man at Bus Stop Richard O'Riordan as Bus Passenger Gillian O'Driscoll as Bus Passenger Lorcan Wall as Bus Passenger Ciara O'Connor as Bus Passenger Avril O'Driscoll as Bus Passenger Lisa Coade as Bus Passenger John O'Connor as Young Man Who Reports Billy Michael Twomey as Bus Driver Michael Murphy as Businessman on Bus Fionula Linehan as Woman on Bus #2 Antoinette Hilliard as Woman on Bus #1 Kieran O'Leary as Security Guard William Duignan as Billy Murphy's Friend