For mechanics, inspecting an entire car takes about 9 minutes (45 seconds give or take, per part) Could we get an inspection that inspects all parts at once, but keep the way it is to repair each part separately? It seems rough to ask a client to just please wait 10 minutes while I inspect everything, but then they only need to repair 1 or 2 parts really.

To see this working, head to your live site.
The way the script is setup its not possible at the moment, however Mechanics can have a cheap beater car on the lot as a loaner for someone who wants to leave their vehicle or they can just interact together, also they can call for one of their vehicles if they have 5k burning a hole in their pocket.