As I indicated in my previous post, getting an EMT certification is less that useless to have any impact with an adcom. It can look like you are just getting to add to your ECs. Several years ago, getting the certification was a "fad" with premeds and quickly was known thru out the adcoms, becoming a meaningless EC.
However, getting an EMT, and using it in either employment or, better still, in a volunteer squad that has possibility for advancement and leadership positions can be an excellent EC. If you stay with it for sometime will show commitment. However, do not make EMT work your sole clinical experience. Get more in a hospital or clinic based setting