One of the bit's of advice I read about creating a cover, is not to try and make it an exact representation of an event in the book. So in the book itself there are: buses, blood and tickling (but not joined at the hip).
Incidentally Amazon have given me the option of doing a free Kindle (or e-book) download offer for 5 days (out of which I am hoping to garner some reviews). However I am not sure at the moment whether that applies only to UK readers (will advise at the time). So I will be doing that in a week or so (once I have worked out how to use Twitter)