Sentence 1: I heard the sound of the cat door open and close. 
 Sentence 3: A small rat was running down the hall with the cat behind it 
 Sentence 4:  I screamed loudly which prompted my husband to come running 
 Sentence 5:  After a few minutes he disposed of the now dead rat 
 Option 1: I saw something larger than the cat out of the corner of my eye scurry past me. 
 Option 2: I saw something out of the corner of my eye scurry past me.