B767 Technician discovered the escape slide dropped during an overnight maintenance check; repair of window shade; and removal of emergency door.

Narrative

We were tasked with replacing the window shade on the left side and the emergency door. After completing the initial installation of the window shade; we realized it was not properly fitted. Based on this observation; we opted to follow an alternative installation method outlined in the Aircraft Maintenance Manual (AMM); which required the removal of the emergency door.We began the process by deactivating the slide; following the correct procedures as outlined. Partway through the task; we paused to double-check our progress and ensure that the work was being completed thoroughly and correctly.Recognizing our limited familiarity with this particular system; we contacted our lead for further guidance. After explaining the situation; our lead instructed us to halt the current procedure and begin reactivating the slide.During the reactivation process; we heard a loud engaging sound. Concerned that the slide may have deployed; I immediately went outside to check. Upon not seeing the slide deployed externally; we assumed the sound we heard was the system engaging itself back into the armed position.However; after proceeding downstairs to de-pin the slide bottles; we discovered that the emergency door slide had actually dropped. After verifying that the slide had not deployed; we followed protocol and promptly notified the appropriate personnel.It was only after this incident that we were informed that certain open logs; such as this one; are often deferred due to the extensive nature of the procedure; which may not be suitable for a simple overnight maintenance check.One suggestion I would offer moving forward is to establish clearer communication between management and the maintenance team regarding which open write-ups can be deferred. This would help prevent similar incidents and ensure that tasks undertaken during short maintenance windows are appropriate for the time and resources available.