If it were mine, I'd pinch a small piece of electrical tape over the disconnected wire, without letting any part of myself or anything that will conduct electricity touch the exposed part of the wire. Then I'd peer in and see whether I could see any other exposed, disconnected or broken wires.
If I didn't see anything, I'd cut a piece of black plumber's tape large enough to cover the open area in the top of the housing where the hot shoe used to be. After that I would see if the camera functions normally except for not having flash. I don't think I would try to use the built-in flash, since the wiring problem might have affected it, too.
Would the flash discharge kill a person...I personally wouldn't want to test it, but I doubt that it would. It's going to be high voltage, but low amperage. To use an analogy with water, voltage is like pressure, and amperage, or current, is like the amount of water being discharged. A squirt gun can develop high pressure, but the current of water it puts out is very small--it could irritate you, but not hurt you. But if you were hit by the water pressure a squirt gun can develop, but with the current that can pass through a firehose nozzle, it would probably knock you down, and might break bones.
Another high voltage, low current, electronic system is an electric fence, meant to contain livestock or to keep livestock from damaging a permanent fence. My electric fence charger puts a 10,000 volt charge on the fence wire very briefly every second or two. If you, or an animal, standing on the ground (which makes part of the circuit) happens to be touching the electrified wire at that moment, you or it gets zapped...but never killed. I accidentally touched the fence a few weeks back. Yikes, it was no fun. But it didn't damage me. It was over so fast I don't think I even had time to utter any colorful language. I bet the electric fence would set off an electronic flash tube. I'm not volunteering to test it though
. I'm also not suggesting anyone should touch a charged capacitor in an electronic flash system. I'm just suggesting you might live it that happened.