Don't matter if he ain't have it on him if he already fired it. Once you discharge a firearm at the police they automatically gonna be ready to use deadly force. If you shoot at them you giving up your protections when caught also cause normally you got protections under the 4th amendment and the Ohio law changed last month so you don't need a permit to carry concealed or disclose you have a firearm anymore. They would've never known he had a gun if he ain't shoot and one officer even tried to tase him while they were running.
The detail about the case will be, did the officer that fired the first gunshot mistake the taser being fired by his fellow officer for Jayland firing when he was running. Cause they're supposed to yell repeatedly "Taser" or something to that effect to make it know they are deploying a taser but I didn't hear that in the video.
-EDIT-
Actually it looks like 2 different officers fired tasers because you can hear them being deployed in the video and see them on the ground when they start the actual shooting, neither officer yelled they're deploying the taser though but the shooting starts a few seconds afterwards.