Driver ants don't eat everything, in fact the diet of most driver ants is very limited (Eciton for example often kills small frogs, reptiles and snakes but does not and cannot eat them).
Yes, there are ants that eat meat (some species of driver ants do and some "normal" ants like the australian meat ans specialize in it) but the majority of ants doesn't really eat animal meat (they specialize more on eating insects and other arthropods).
Also we already have that? There are levels with dead shrimp and even dead fish to eat.