mind scratching

so i was over my buddys house trying to help figure out why he has a loss in power. good fp, good hpo, swapped my pcm and idm with no change. then we go to check the ohms in the vc's. checked from externaly from pin 2and 3 then 3and 4. checked good. then we checked between 2 and 4 figuring we shouldnt have a completed path but we did. so we check my truck and my truck also did. then we go to do a buzz test just to see on his truck to see how the injectors sounded. well 5 and 7 sounded really weak and figured that was his problem but noticed that the plug wasnt even plugged in. thought that was very strange that they fired while not even plugged in. did the same test on my truck with the plug unplugged and had the same result.
so my question is how can the 2 injectors fire while not even being plugged in?

Will have a youtube video tonight to follow.