Plot Point (Spoiler)

I love TGAMC.However,I could not help but notice a plot issue.Mr.Kelsey was unable to get into the mansion when Luther,judge,jury,etc all enter it after the judge orders it in the courtroom.The judge ordered it during the day,he told everyone that they would all reconvene at 11:00P.M. at the Simmons mansion.Shouldn't that have given Mr.Kelsy plenty of time during the day to sneak into the mansion & rig everything just as he's done before?Were the police there all day guarding the mansion so that's why Mr.Kelsey could not get in before everyone else?Also,when Mr.Kelsy is playing the organ music at the end,how come only Luther heard it outside the mansion?I realize that everyone else had left but they were all on foot.They could not have gotten that far & not hear the music could they?