Miller was not part of the experiment because his presence was not required for the equivalent real-life occurences in the experiment to happen, unless of course you think every lightning bolt has a divine purpose behind it, and even then the theory of electromagnetism provides a much more plausible answer. You're arguing for the idea that God is directly behind earthquakes and weather patterns, consciously guiding each one because someone can set up a weather or an earthquake simulation (who does the supercomputer programmed by software engineers represent?). You're arguing that every murderer is guided telepathically by God because crime scene detectives can set up recreations of events they did not witness (who do the detectives and crime scene investigators represent?)
Flipping the switch on the lightning bolt and compiling the molecules in a vessel don't count as being part of the experiment because there is no intelligence required in the equivalent events happening naturally. We know why lightning occurs, and why carbon hydrogen and oxygen would be on the earth, and we also know how the earth got here. None of those explanations require a deity. Stellar nuclear fusion accounts for the elements without the need of a deity, the electromagnetic force accounts for lightning, and the forces of gravity account for the earth. Merely mimicking these natural occurrences for the sake of experiment does not constitute a designer. Sorry.
Comparing a lighting bolt striking the ground to the creation of a cell is like throwing paper and a typewriter in a tornado and expecting to get an unabridged dictionary.
All I can say is words escape me...
Have a nice life.