Corrected entry: In the scene where the doctor smashes the glass on the sliding door near the lock when setting up his alibi he correctly does so from the outside but leaves the door open. With the door closed It would have been obvious to anyone seeing where the glass had fallen that the door was open when the break-in was done so making it an inside job.
Dale Adams
20th Mar 2014
Correction: You smash the glass and use the hole to open the door. Then you can just walk in there. You do not have to crawl over the splinters.