1) You are not going to die. (this is what the Doctor in the clip said).
I think she used a closed question to get him to stop talking and reassure him at the same time.
(2) What makes you think that Chris?
this is a open question and will get him to talk more in a situation where he is gasping for every breath
(3) If you just slow your breathing down you will be fine.
The situation is uncontrollable hence this response will make Chris think he is not making an effort
4) Everything will be ok, stop talking, to save your breath.
This will response will make Chris feel he is being asked to shut up
