I'm drinking S.c. on the rocks and something in the glass just exploded?

its about 71 degree in my room, the sc has been sitting in the same temp, just purchased, it was in a small 8 ounce glass with about 4 ice cubes and as they melted down, and about 45 minutes into my drink, i had it up to my mouth and heard a pop and some liquor splash me in the eye? can anyone explain this has this ever happend to anyone on here