something simalar happened to me and a workmate a couple of years ago but it wasn't an orange flash it was bright white, the only way i can describe it was like a full beam headlight being flashed but we was in a stairwell with only a sky light,with noone else in the building this was in a large derilect building with no electricity, useally you can find some sort of explaination, but me and my workmate couldn't find any logical reason, really freeked us out, i continued to work in this building for the next 18 mths and i was allways first there on my own because i had to unlock and every morning had to walk past this stairwell to unlock the fire escape to the car park, it allways felt cold and like i was being watched, use to shit me up. in your case both times you were useing a screen so maybe there was a reflection but after what i saw and felt i wouldn't rule anything out