The interns incorrectly instruct Dave to blow into the incentive spirometer. Correct use of the device is to breath in slowly through the tubing, hold your breath for a few seconds, and then breath out.
The patient awaiting a face transplant - the one they call "Blowhole" - has no visible lips nor moving mouth parts. Yet he is able to clearly form the "b", "m", and "p" sounds which require the lips to interact with each other, as well as the "f" and "v" sounds which require the teeth to interact with the lips. The actor was either wearing a full prosthesis and speaking with his normal mouth behind the prosthesis, or his entire dialog was dubbed later without the prosthesis on. A patient with such a facial deformity would have a severe speech impediment, particularly with the letters listed above.