Benzodiazepines and alcohol usually are not fatal unless your purposely are trying to make them so, or are just being such an dummy and are consuming wrecklessly and irresponsibly.
But that would include swallowing a whole hell of a lot pills and booze. You won't end up dead.
Alcohol has effects on NMDA channels and Kir channels which are inward rectifying potassium channels. Which gives alcohol stimulating and dissociative effects in addiction to its typical GABAergic (ie benzo-like effects). So expect some of that to be mixed in.