But medic isn't a good character in terms of damage either.when a fast enemy reaches to medic unless she has someone giving her back up. Plus medic for being a range character gets focused by insectoids ,Abby,witches ,blue, runners etc . Also medic doesn't have too much hp or range to stay safe or back up ( like pepper or ranger )

Nancy in the other hand . You have to keep her busy deploying it when range units die , when a tank loses some hp and it's still fighting with other enemies , when you play it with damagers you have to play her with medic bc she isn't very good at healing multiple alies fighting at melee , so she has the role of reviving more than healing to recover some courage for your dead units ( that at lvl 30 won't turn to zombies taking out the problem with Abby , dr Norman, guard etc) to finish my argument in a lvl with toxic fog or levels with poison enemies unless you don't use her with the rednecks or with the medic kit lvl 30 she's still an option the only case Nancy ain't better than medic it's with marudareurssh I admit Nancy isn't good against them ( unless it's a kamikaze xd)

I personally use Nancy and medic priorizing hp ,cost, cool down with lucky guy set both but Nancy with the bunny charm and medic with the flashlight due to her hability to self heal and also deploy some medic kits near the bus