Arcing across coil terminals

Here's what I think is happenin. I think it's arcing from the plug wire on the cap, to the coil wire through the boot and to "whatever" it is grounding on at the coil. Me and Kirk were workin on his Chevelle one day after school. We were adjustin the valves. Hot little 307 Chevy......we had everybody snowed it was a 350 cause it ran so good. lol Anyway I had removed the coil wire. On the factory coil mount on those late 60s (his was a 69) and early 70s point type Chevys, the coil was mounted right next to the distributor, pretty much vertical with the coil tower only about 4" away from the coil nipple on the cap. I had the coil wire removed so it wouldn't start. Ha! I told Kirk to bump it to get the cam on the base circle, and BAM it busted right off with the coil wire sittin on the cowl under the the wiper blade. So don't think for one minute that the spark cannot travel a great distance if all the conditions are right. We found out the hard way!