Scientists like Francis Collins and Kenneth Miller can only do good science by leaving god outside the lab. They compartmentalise their lives.
Says who? So what if someone like Francis Collins prays for help in his work and believes it makes a difference, how are you going to stop him?
You're exhibiting an instance of the "all true Scotsmen" fallacy by defining your terms in a way that provides merely circular support for your conclusion. As in when someone may say that all true Scotsmen wear nothing under their kilts, and another may point to an example of a Scotsman who wears underpants. "Aha!" comes the inevitable reply, "but he's not a true Scotsman then, is he!"
So you claim scientists must leave their theism at home. But that is not a description of the world as it actually is, but merely an assertion by you as to how things should be. Certainly there will be scientists who pray on matters involving their work or in some other fashion "mix" their science and theism in ways that might offend you. But then comes the inevitable retort from you: "aha, but they are not practising real science when they do that!"