Honestly once you realize this part Mission 43 becomes a lot less hard hitting.
It feels like Huey was meant to be a very ambiguous character in terms of intent so when he criticized you I felt like it was a bit of a red flag in terms of who was ultimately right or not. Then when nothing comes from that entire segment in terms of developing Big Boss' character and is only used as an excuse to kick Huey out, it really ruins how much it resonated for me in the moment.
Like, I was convinced that was going to be Big Boss' descent into becoming a demon or whatever but "nope we're Diamond Dogs lmao". As it stands the entire sequence literally exists probably because Kojima thought it was cool but instead like everything else it feels like it came out of nowhere.
Man that whole sequence was amazing, about to walk into that room with the men scared that Venom would kill them and then entering and having them say that "let the Boss decide" and then salute and hum the main theme. I was like fuuuuuuuuuuuuuu
Anyway, why would that event be his descent into becoming a demon? He didn't do anything evil or wrong there.
He shielded the Diamond Dogs personnel from a traumatic experience by going in alone. And even after finding the mutation he tried shooting limbs and using CQC till the end on those infected men instead of killing them right away. He killed the infected men, who were as good as dead anyway, to prevent them from spreading the infection to the rest of DD and beyond. He did a good thing.
Had he lost it and became a demon during this, it wouldn't have been because he did something wrong or evil but because he cracked under the pressure of having to do something painful for the greater good.
If anything, this is probably the point I would pick where Diamond Dogs became more Venom's than Big Boss's. He even established a brand new tradition that would have the men remember their fallen comrades when going into battle and gave a whole new meaning to the name Diamond Dogs.
So yeah, this moment was very significant and very memorable. It was also the reason that I wasn't surprised when people at MB would tell Venom that they would follow him no matter who he was after Episode 46, since at that point he had done enough that they were loyal to him personally.