Upon stepping on the planet, Kirk had felt a stinging sensation from his cuts as Spock spoke to the crew about the unknown infections and diseases, some fatal and that they should keep their suits on at all times. Fatal?  Kirk's gaze shot up to meet Spock's, "Can the infections get into cuts?" Everyone was kinda surprised by the question, but of course Spock was unfazed. "Yes, they can." Spock responded, raising an eyebrow. Kirk didn't care about Spock now, he could die on this planet! This is how he would leave! 

Kirk ran off to where the others couldn't see him, there he took off his suit, he felt the cool breeze over his cuts, the air soothing the stinging pain of the cuts. He could swear that he felt the infection burrowing in the cuts, after only a few minutes, he started to become unsteady, his vision blurred, the crews' voices becoming distant, then he blacked out.