@The:
Doflamingo headed back to the palace because he was confident that it was impossible for Luffy to escape the Coliseum.
It wasn't.
= Doflamingo underestimated Luffy.
Doflamingo has no idea where Usopp and Robin are, but he assume they are of no consequence. He also assumes his underground is impossible to reach.
Usopp and Robin have currently infiltrated the underground.
= He underestimated them.
Doflamingo is being careless. Yeah he "doesn't know all the facts" but when your empire lies in ruins because of someone you dismissed as clearly inferior, thats just a sad excuse.
HE HEADED BACK to the palace so to talk to fujitora. Which is more important because if an admiral is on your side, hell breaks loose. HE IS NOT COMFIDENT WITH LUFFY IN GENERAL, because he had a conversation with luffy and planned out to let luffy join the contest so he will be separated with his crew. And no one escapes the coliseum because the tournament is ongoing. HE DIDNT KNOW THAT LUFFY BEING LUCY HAS ANOTHER LUCY IN LUCY. WHICH ALL OF US DIDNT KNOW WHO THAT IS, (YEAH IT IS SABO ) and is willing to help luffy get his hands job-free of the mera mera fruit.
I never said he didnt underestimated other sh crew. HE IS NOT CARELESS BEFORE THE ARC HE PLANNED EVERYTHING OUT EVEN FAKING THE SHICHIBUKAI TITLE AND SEEING WHO HIS OPPONENTS ARE.
WHAT WE ARE SEEING NOW, AS IN RIGHT NOW, IS A CLEAR PICTURE OF DOFFY BEING A GOOD PLANNER WHEN IN FACT EVERYTHING IS A MESS. YEAH YOU CAN SAY HE IS UNDERESTIMATING LUFFY WHEN ODA SHOWS US PICTURE SAYING "i underestimated you straw hat". BUT! BUT UNTIL THEN!!! DOFFY DIDNT UNDERESTIMATED STRAW HAT. HE EVEN ACKNOWLEDGED HIM SAYING HE IS SOME GREAT MAN 2 yrs ago. (Idk the exact words)