MinHurtless, really max? lol.
I stop reviving if I know they aren't doing anything or are purposely leeching. I only revive if the person is near me, but I will not go across the map to revive someone especially if there is a high chance I could die trying to revive them. If 3/4 people all go down in one area (outside of an objective wave) I usually take that as a warning that I should avoid going to that side of the map, unless I feel I can take on all the aggro, as I most likely I will die to. It all comes down to wither you have to go out of your way, putting yourself in danger, and diverting potential damage to the enemy to revive people. Every second reviving means 1 second not killing, thus a longer game.
I usually will go out of my way to revive pugs if they aren't leeching or are dying every second. It really depend on how generous I'm feeling. I do like meatshields, as they make me feel pro.
If you want to be a medal cow then ignore everyone above and just keep reviving. I would probably ninja change the difficult next game if I was host or just only use a Common weapon next game, if I was dealing with the same players again.
You can also use ladders to hide your missile launcher for kits that can't hide it with heavy melee, MinHurtless.