Is a what now?

Is a what now?
twimii is walking out of her apartment. There is a garda (police officer) outside her gate taking to three boys. One of the boys is saying angrily 'It wasnt us!!!'. twimii is closing the gate behind her, she looks at the wall and gasps 'OH!'. The L has been changed to an N. twimii happily says to herself 'well, that sorts it'. The garda turns around and looks at her puzzled. She looks up at him and says delightedly 'I am in no way responsible for that!'. She then walks off on her way. The garda and the three boys stare after her in amazement. One of the boys then says to the garda 'You'd want to keep an eye on that one' The garda's eyes narrow as he watches twimii and he says 'Yeah'.
Getting a bit colourful with the old language