Can 10-100mA kill a person / be deadly?
A circuit that is drawing 10mA or 50-100mA is quite a bit different than a circuit that could push that much current through you.

Figure out what the resistance of the human body is, then calculate how much voltage you would need to force that much current through that resistance.  You will quickly see how your arduino is incapable of forcing even 1mA through your body.

Remember, just because something can source 10mA, doesn't mean that it can force that current into anything.