Health Gun
Basically, something like the Medic Gun in TF2. However, have a limited amount of health in the weapon that has a decent length cool down. Around 3 meters range, heals at about 50% the speed of a Sawbones medpack and has around 10 seconds of charge on a 30 second cooldown. (basically 1 second healing per 3 seconds to a maximum of 10).
This would make her very suited to a full on support role for a super heavy Merc and still able to revive at range to make her more well rounded.