He doubled up in her arms , then went limp . His body rolled over , his face wedging in the roots of a drift stump . Rin struggled to turn him over again ; small pebbles stuck to the bared front of his body . One hand still clamped over the broad smear of blood .

Give answer the following question using evidence from the above passage: Why has this person 's body gone limp ?
This person is in the midst of potentially dying .