Sergey stared forward at the man charging him, and he watched the man on his flank. He turned his body and felt something go through his leg. If he hadn't had turned he wouldn't have one however. And thankfully his allies should have made it to their lines as the target wasn't them for the most part. But he slowly let the shield go, letting it stand there without him for a moment as he took a step backwards out from behind the shield as a man ran into it. 

It was something like out of football practice where a linebacker hit a mannequin and tackled it. But with an armored man and a shield. 
With Sergey using his large rifle as a hammer to smash down upon the mans head to try and knock him out, after all it is an armored suit, so a little trauma to the back of the head shouldn't hurt that much right. He then took the opportunity to grab the mans far wrist and pull it around to his back only to use the man as cover since he was on top of his shield. If his friend couldn't penetrate his shield then it shouldn't this mans armor in theory. His other hand went to hold the other mans closer wrist down. 

"So friend...if you can hear me, how good is this armor I would say I'd but it, but I don't know if it is better than what I wear... it seems bulky and hard to wield. Or did you just plan to throw yourself at me like that?" he asked as he sat there behind him getting shot at from his new 'friend's' friend until someone else could deal with the flanking man until he either got close