Dead pin on Nano?

Hello all.

I'm currently working on a quadcopter project, and I'm at the stage of hooking up things together. Today, I think I made a mistake. I connected all 4 of my ESCs to my Nano. Looking at the servo wire, I thought that all three on all ESCs have to be connected. I connected the all servo wires (V, GND, SIGNAL) from all 4 ESCs. Now, my pin 5 is fried (no signal being outputted whatsoever). I think connecting all the V wires from the ESCs to my Nano fried it. But why specifically 5?

Now, I learned that only one of 4 ESC's V servo wire has to be connected. Doing so already gives the Arduino a 5v source and the only things that need to be connected are GND and SIGNAL. I connected 4 voltage wires (20 volts flowing into arduino?)

Does this mean that I ran 20v on my Nano? If I did, why is my Arduino still alive?

Thx in advance.