Infiniti Q50 shaking and making noise at idle.

What is your question?

Our Q50 was shaking and making a knocking racket at an idle. Went to park the car to listen, shut it off and let it sit for a minute. Started it, started doing the same so I turned it off. Tried to turn back on and it wouldn’t. Local infiniti came to tow it. It is under warranty and they are saying that they looked at it, can’t find anything wrong but it won’t even turn over and are waiting for someone from Infiniti Corporate to come and look it over. Does anyone have any idea why it would do this and why they are sending corporate? Does it sound like they are trying to void my warranty? PS: as you can tell from my question, I know nothing about cars. I was just getting lunch for my daughter and it did this! Help???

What makes this problem better or worse?

It was at an idle. Happened fast

How long has your 2015 INFINITI Q50 had this problem?

2 minutes and then it died