hard to say really as none of us are on admissions committees. each school does things a little bit differently. for some, it might depend on the school you go to or if they for some reason have doubts about your abilities.
if you go to a reputable school without grade inflation, they might overlook a weakish mcat score.
if you go to a questionable school or one known for grade inflation, they will probably want to see good mcat scores.
if they have doubts about your ability to do well in science courses, mcats will probably weigh heavily.