I doubt the medical staff would participate and the idea of an execution is that it’s supposed to be quick and painless.

The same question has crosses my mind too though. Seems super bizarre to decide to do something like this and then pivot to life saving critical care as soon as you fuck up. I read that the people they have to obtain IV access as not well trained so the IVs tend to infiltrate (leak into the subcutaneous tissue) leading to only a partial dose being delivered to the bloodstream.