This is an Explanation for Lucille's Actions during the meltdown:

1: The remote detonation is illegal itself. 

2: They also wanted to blow up most of Lucille's research just for themselves/to get rid of all evidence completely and deleting it off of their stuff. Didn't work so well since Cam found some of them. How they survived is unknown.

3: They blew it up after Urayne was discovered to be sentient. It was illegal in the first place. Creating pokemon was illegal, never said anything about sentience. They detonated it because Urayne becoming sentience wouldn't help their evil plans. The whole "to change it for the better" doesn't make any sense because they detonated it because Urayne became sentient. "Experiments like you are highly illegal" (Lucille to Uryane) Never said anything about sentience. 

4: They activated the remote detonation sequence without warning. They obviously knew the effects of a nuclear radiation, causing all the nuclear pokemon. Even if they didn't know... Its a nuclear bomb condensed in a reactor and restrained with some shielding. Everyone goes to school. History is a class. Hiroshima is a nuclear bomb. Science says that uranium is bad for humans and Pokemon. Common sense says that exploding a nuclear device unexpectedly is stupid.

5: Blowing up the whole plant was a overreaction. Uryane couldn't escape anyways without outside help (or it would of done so earlier. It was alone for very long), and it is clear that Lucille had no intent to let him out. (Until the thing was completed.) "They told me about the world beyond the lab... A world I would sometime see and my purpose... to change it for the better" (Uryane's memories of Lucille's talking to it)

6: Her honor/good bias to the experiment. 

7: In the statement of the possibility of the interface causing the mind to be frayed, lines such as "possible" was said. This confirms that no one had any idea that the relay could do damage to the user after prolonged use, since testing it for 10 years was very unlikely to have happened (considering it was never shown to be tested for 10 years. The helmet links directly to Uryane, he would of mentioned it in the flashback if it was done, otherwise it was tested when unlinked.) and he didn't know the interface's effects before the incident. The researchers didn't know, if they did then Cam would of known. "...Its possible the interface was responsible" (Cam) So when Lucille entered she assumed she would be fine and everything would be normal when she was eventually rescued. Also lets consider Lucille has a son/daughter and would probably not make an irrational decision (that affects her) for a failed genetic experiment.

8: Betrayal and Anger causing irrational thinking. "Dr. Larkspur is a goddamn coward. He'd rather destroy all evidence you ever existed." (Lucille to Uryane)

I think this provides a decent explanation for the behavior during Pokemon Uranium of Lucille's actions.

Feel free to discuss in the comments. If it is good enough and makes a good point I will probably add it.