Theres absolutely no reason an infared camera couldnt survive a microwave. All you would need is for the camera body to be outside, and to have a mesh blocking the sensor. You wouldnt be able to go through the door if the door is glass(not that ive ever seen a glass microwave door) because glass blocks infared, not sure about plastic. either way though, you could just cut a hole, remove the plastic, and then replace the mesh. Youd have to do some software work to ensure the camera is not picking up the heat from the mesh.