how much can you get slipped during volatile events?

Hi,

I was wondering how much you would get slipped through your stoploss if you are on the wrong side of a trade during a very volatile event. I'm not talking interest rate decisions, ( however I'm also curious about as I don't trade such events that) but more like events where a sudden move happens very quickly. best example I can think of now would be the swiss franc which unpegged from the euro or brexit? any ideas / experiences?

There is no limit, really. Expect the worst, especially during black swan events.