“10 minutes acceleration... 10 minutes deceleration”
That’s not how rockets work. An eight minute burn at >1g to 3g’s will take the rocket to orbit (~two minutes for first stage, six minutes for second stage). For a suborbital flight, it will be less then that. Upon descent, re-entry into the atmosphere will provide most of the deceleration, then a landing burn for soft landing.
To make it half-way around the world in under 20 mins, per Musk’s claim, that’s the way the rocket would have to work.