Sentence 1: Sam put a length of saran wrap on the toilet as a joke. 
 Sentence 3: There wa a silence and then a shout 
 Sentence 4:  Sam's brother burst the door open and ran after Sam 
 Sentence 5:  Sam escaped because he was faster than his brother 
 Option 1: Sam didn't realize that nobody was home, so the prank went unnoticed. 
 Option 2: He waited until his brother went to use the bathroom.