"Fallen" his ass. He'll concede maybe physically, since it's obvious he's just collapsed, but Nicholai doesn't have the whole picture.
Actually, the scientists had been monitoring him incredibly closely ever since they had administered the injection to see what effects they would wreak. HUNK was among the first of the top-level employees to receive it with no suppressants, given that he needed to be in top form and no sickness bringing up down.
They had warned him the results would be unpredictable. He just thought that he would be able to deal with him. They had warned him he may begin trying to reject it, the same way the body does a virus or bacteria. Or even an organ.
Even in this twilight-state, he can feel the blood lust rolling off of the Jackal in waves. It had the stench of carnage to it, and he can feel his adrenaline levels spiking in a misplaced combat-high empathy.
Thankfully, it serves him, because it gives him enough energy to pull his feet under him, over-spent muscles twitching enough to be felt through clothing.
But in the place of a cold anger at himself for the debacle going wrong, an unexpected rush of relief fills him. Nicholai is fulfilling an assist to a "hurt" member of a squad he isn't even quite a part of yet.
It's enough. He knows he can drop pretense from here.
His mouth has gone dry, and he can hear his lips peeling apart from the grim line they had made, enough to say, his voice barely above a choke, "It's the injection."
His heart gives an erratic thrum, maybe something that Nicholai can feel, since his hands have cupped his ribs and chest. It forces HUNK to take in a deep breath, transferring some of his weight to the Russian behind him.