He dies because he spawns without ammo, he tries to run of to the nearest crate to reload, falls of the edge and dies. The problem can easily be fixed by giving him ammo.
In script:
This addMagazine "30Rnd_762x39_AK47";
The problem happens because the building is does not have any path finding for the AI, it falls back on natural movement, so it doesn't "see" the edge.