I pretty much never bother opening the laptop until I'm at the hospital. There are a lot of reasons for that, but a laggy UX isn't really one of them (despite the fact that the UX is indeed super laggy on any ePCR I've ever used). Instead I use a pen and paper (or a pen and a strip of white medical tape on my thigh, for a more critical patient).
The reason I don't bother is because the whole UI is just too much of a hassle. Not the application frontend, the whole thing. The laptop, the keyboard, etc. With a pen and paper I don't have to keep taking my gloves off and putting new ones on each time I need to switch from documenting something to caring for the patient (a pen is trivial to wipe down, or just toss if needed). With a pen and paper I can jot simple notes in a shorthand I'm familiar with, rather than having to navigate to the right page to enter the information I want to record at the moment.
I know very few providers that bother touching the laptop prior to arrival at the hospital. Generally we write notes on paper, then bring the laptop into the ER and start typing while we we're waiting for a bed for our patient (it's not uncommon that this takes long enough to get the whole chart written). At my agency we have two hours from when we transfer care to when the chart has to be signed off and locked.
I also chuckled at the suggestion that "0.1% of PCRs have errors that waste an hour of a doctor's time". In my experience 0.1% is pretty much how frequently the PCR gets reviewed at all in the ER, and anything important enough to spend an _hour_ on would have been mentioned up front during the transfer of care (nevermind the fact that an hour is an absurd amount of time for a doctor to be spending on a single patient).