I have addressed it. As I've always done in the past, I let you make your own mistakes. And using a plasma grenade is a fairly significant one, which I thought should have been obvious to you. I don't know what effect you were trying to achieve but plasma is the most double-edged sword in the grenade category. Surely you could have achieved the same deadly effect with a fragmentation or monofilament grenade. Two lines of text is not very much for me to go on and I am certainly not a mind reader. If you want me to be aware of the details and intentions behind your actions, you need to write them down. For example, "Lisa waited until the Nepleslians had taken cover before throwing the grenade, set to a three second timer. She had already cooked it off for a second and launched it at the Advanced Type Mishhu."
But if you wish, let's go farther in depth with this and examine what else happened and could have happened. The room is pitch black after taking out the lighting, your Golems are using light enhancers to see in the dark. Sudden bright light with light enhancers? It tends to blind people. Sure, the Golem can react to changes in lighting but not instantaneously nor completely. NAM Plasma grenades can be preset to a timer, impact or remote detonation. Lacking any description of which method of detonation was set, I default to impact detonation. At most, the Marines and IPG would have had a second and a half to prepare themselves before the explosion. If likened to the adrenaline-pumped paintball tournaments I've been in, one second is either really slow or really fast. Usually the latter and is normally, not enough time for the human body to react appropriately. The analysis be received from the eyes and the response from the brain could be transmitted but the actual movement would take longer considering how many parts would need to move for the Marines to take cover or shield their eyes. Eyelids can block a lot of light but not the amount of a miniature sun, you would still be dazed and blinded with purple haze in your eyes.
If my failure to explicitly state this process was the cause, I apologize and will make sure to be more detailed and provide greater explanations in future GM posts.
Things could also have been much worse., regardless of method of detonation. I could be using the 3800K temperatures to fry you inside your suits. Confined space instantly heated up would boil everyone to death and burn up all the oxygen. Or a cave-in. Would you prefer I add these consequences?
The consequences of the plasma grenade in the GM post are fairly minor in comparison to what else, realistically, ought to have happened.
But I won't stop you if you want to leave.