Air carrier Maintenance Technician reported an inadvertent escape slide deployment when moving the door handle to the closed position during aircraft maintenance.

Narrative

While working on Aircraft X; the cleaners had opened the 4L door and the force from the wind gust caused the upper panel of the door lining to be blown off and break one of the mounting clips. since the Aircraft Maintenance Manual (AMM) did not specify opening the door for repair of the clip; i did not believe i needed a monitor and challenge Briefing for the task at hand.After completing the replacement of the damaged clip and reinstalling the panel; I noticed the handle was not fully closed. As I went to close it; I did not observe the position of the arm/disarm handle. Just moving the handle to the closed position caused the slide to deploy. Even though the crew was starting to assemble on the airplane when I got back with the part no one else was involved with this event. This could have caused by the violent racking of the airplane from the wind gust and i should have gone and get some help before touching a door handle. To avoid this; never touch an airplane entry door without monitor and challenge.