Thank you!!
Noticed:
When they left the WH POTUS and FLOTUS were arm or hand in hand till she went around to get into car
They were accompanied by USSS with FLOTUS walking with just a couple around the car to enter
When the returned POTUS got out of car and was immediately surrounded by USSS detail. FLOTUS got out of her side and followed. She was walked in with just two USSS.
So it must have something to do with placement of security