Why does Mr Poole ring for Utterson?

Mr. Poole rings for Utterson because he is concerned about the strange behavior of Dr. Jekyll and believes that Utterson, as Jekyll's lawyer and friend, can help resolve the situation. Poole fears for Jekyll's safety, especially after witnessing the unsettling transformation into Mr. Hyde. He seeks Utterson’s assistance to confront the mysterious circumstances surrounding Jekyll's reclusive behavior and the presence of Hyde.