Have not done it, but it is just resistor throttled direct drive, and driven pretty hard as it is for 5 mm LED's. I don't know if it would "insta-flash", but I doubt it would last very long. That is about a 30+% increase in voltage.
Now a single 16670, that would give a nice low level for dark adapted eyes for a real long time, or a single 16340 with a dummy cell.