Damn! Sorry that happened to you but glad the damage isn't worse and that you got the trans leak fixed. As an anecdote, I was working on my dad's 62 Ford Galaxie, putting in a courtesy light under the dash on the driver's side. I had the battery unhooked. I finished the install, we hooked up the battery, the light was working nice and Dad went to start the car. The light housing shorted on the post on the back of the ignition switch (dash mounted on that car) and the carnage was bad. I thought the car was going to burn up right there. Dad was hustling to get the battery cable off and I started ripping wires down under the dash in a panic. The car didn't burn. My hands were burnt pretty bad. After I healed up I ended up pulling the entire harness out of the dash and most of the underhood wiring harness out and repaired/replaced it with elements from a harness we bought online. It was a big job all for a small mistake. It happens.