AS.LX lever unlocking the entrance door and repair

"The lever comes off completely and the door does not open"

I requested to unlock it, but I couldn't tell that the lever was completely disengaged.

When I checked it on the spot immediately, it was completely taken as declared.When the outside came off and I tried to insert it again, it seems that the remaining parts fell on the back side.The set screw is gone.

After unlocking, I don't have a set screw that fits the length.I thought about cutting it with a grinder, but let's stop going back and forth on the stairs on the 4th floor.I processed it so that it fits the set screw fixing part, and attached the M4 countersunk screw.