OP -
Under my care, I would likely have started this case with an intubation, and, if required, everyone would have waited for me to safely do an AFOI. With each detail you described, it sounded worse and worse. I'm interested as to why you didn't choose intubation right off the bat.
I've been in practice as an attending for ~26 months. I have developed a pretty good rapport with most of our surgeons/proceduralists, and work to be efficient and facilitate patient care/work flow. That's my capital. Fortunately, those few times I need more time, I spend the aforementioned capital by saying "I'm sorry, (whichever surgeon), the only safe way for me to do this is with (insert time consuming but essential procedure here). This will take me a few extra minutes". I don't ask permission and, if asked about it, I say the patient requires it for safety. Once a surgeon turned around and left, but that's the worst I've gotten. As Chocomorsel deftly noted, this is my malpractice (and license) - and the PATIENT'S LIFE, BY THE WAY!!! - at risk. Why chance it?
I admit I had not considered that I am simply too unskilled to effectively get sick fat patients through a sedation case. That could certainly be true. But until the pulse ox alarms, only one or two people in the room know that something is wrong with the patient's airway or breathing. I supervise rooms with CRNAs and residents. With an ETT in place and vent on, Airway and Breathing are covered, and almost everyone can identify hypotension. Any story that sounds anything like "This is the worst airway I've ever need, it terrified me, I'm far away from any help, and the case involves catheters in the patient's heart" puts placement of an ETT high on my list.
I'm perhaps too conservative. I RARELY use LMAs. If I retire as being branded too conservative or overly safe, I can live with that.