have a careful read davel on the following link.
http://www.rospa.com/homesafety/adviceandinformation/childsafety/accidents-to-children.aspx
'When do accidents happen?
Most happen between late afternoon and early evening, in the summer, during school holidays and at weekends
Factors such as stress, death in the family, chronic illness, homelessness or moving home increase the likelihood of the child having an accident
Some happen when the usual routine is changed or when people are in a hurry
Distractions and inadequate supervision are often the cause of accidents
Poor housing and overcrowded conditions lead to increased numbers of accidents
Some accidents are caused by lack of familiarity with surroundings, for example, when visiting friends or relatives, or in holiday accommodation.'
Accidents seldom, if ever, happen when completely zonked children are crashed out in bed fast asleep.
The children had had, no doubt fun-filled, but also hectic and exhausting, days organised for them by the staff of the creche.
That'll be why they slept so soundly through the chaos and confusion of events of the night May 3rd.