Nuns on a bus

[Tally]

A coach full of nuns were on their way to Lourdes in France when the driver had a heart attack and crashed killing all on board. Being nuns they had a fast track to the pearly gates, on arrival they were met by ST Peter who informed them although they were nuns they still had to confess their last sin, and then they could enter the kingdom of heaven. St,P called the first one up and she told him that she was a nurse in the war and she saw a naked soldier. St P said " rinse your eyes in the holy water in the font and you may enter, she did and went in. The second was called up and asked the same question, she answered that in the same war she was also a nurse and she was giving a soldier a bed bath and touched his manhood, she was told to wash her hands, she did and duly entered. St p was just about to call the third when there was an almighty commotion from the back as this nun came hurtling forward to which St p said ' why the rush ' to which the nun replied ' if sister Mary is going to put her arse in there I need to gargle first 

[Globalrider]

I don't get it!