Its supposed to be drive-thru. If its not, then add opening the garage door (one coming, one going) and waiting in line to the supposed 90-second swap time.
These are literally all engineering problems that can and have been solved. You have no idea what you're talking about as it applies to this situation.
An engineer at Tesla, who has actually worked on the problem, rather than someone who believes he has enough information to make a judgement on a problem which you have not studied or thought about for more than a few minutes. /internetproblems