Do any of them listen? The infected. Has speaking to them ever worked?

I understand that you are worried about your friend, but it would also not do you any harm to be examined while waiting. If you are, the both of you infected, what good will you do him? And from what you say, if someone is capable of taking him down and keeping him still, it will not make a difference whether you are where you are, or at the hospital.

They could, surely, bring Peter to you.