the wounded soldier is no longer just a man begging for mercy - he is infected with something dangerous, which makes him aggressive and possibly uncontrollable. His outstretched hand may now mean not a plea, but an attempt to grab the protagonist, which increases the sense of threat.
The soldier's eyes, wide open and seemingly filled with fear or madness, now look like a sign of loss of humanity. The blood stains on his clothes are no longer just traces of battle, but perhaps the result of his own aggression.
The chains in the background can be interpreted as a symbol of restriction or control over the infected - perhaps he was captured or locked up, but was able to break free.
