I find it odd that the Aero Commander acknowledged an inbound jet 8 miles North East, and decided to take off to the North about one minute later. Without a quick CTAF call to check on position before rolling ?
UJS made all the correct calls so did VQG for that matter. The problem was UJS rolling call was at the same time centre kept calling VQG so they didn't hear it as they would have been talking to centre. It took UJS 90 seconds from taxi call to airborne. In that time VQG was dealing with two other aircraft and talking to centre. My guess would be that VQG crew weren't expecting UJS to get airborne that quick