Do it every day for the next 50 years and you may develop some risk of headaches.
Seriously though, why was it switched on, on the ground? If it was for maintenance you shouldn't have been in front of it and if so why did you walk so close to it? It just seems a very silly thing to do.
On a one off basis there is little or no chance of anything happening to you, but on a very regular basis you would be asking for trouble.