Alright, I'm getting a tad pissed off at this. My character jumped to avoid a grenade blast. Sure, it was in a different room. But perhaps you'll remember this excerpt from the intro post from Turn 6 of the last mission:
Farzis grenade exploded with a ponderous thump that hit the marines with a flash of white, suffocating pressure and scorching heat. Pieces of shrapnel whirled past, rotating and screaming like microscopic banshees. For a few moments all the marines could hear was a high pitched shrill tone as their ears overloaded from the massive sound of a grenade exploding in a confined room.
Now, also consider that, in fact, the position was within the blast radius, based on this description from Nick's second post of Turn 4 of this mission:
Honeysett threw a grenade and it landed half way down the hall way. A flash and a heat wave followed instantly by a sound resembling a be hive rushing past in supersonic speed as a pieces of shrapnel rotating wildly flew past them.
With regards to the fact that Duncan "didn't go back in", IC, Duncan dove for cover, got up, looked into the kitchen as Farzi fired another grenade, then immediately told his concern to Quinn. Threads usually last for days/weeks, but, particularly in battle scenes, generally account for much shorter periods of time. What you're calling desertion is essentially changing position by 5-10 feet for 15-20 seconds. I didn't flee the scene.
Also, if I'm correct, what you're essentially arguing is that in a situation where a platoon of Marines was duped into gunning down as-of-yet unknown numbers of marines/secret servicemen, the one person who should suffer permanent consequences is the only marine who suspected something was amiss, because he's apparently uppity about taking a faceful of shrapnel.
Shenanigans, I say.