Lets be honest that was PIS nonsense.
Ghandi was so fast he circled all of egghead in seconds, he alone couldve caught up to Sabo.
Thst whole thing always annoyed me. Lol. There was such a simple answer to it as well. Once Sabo gave up on saving Cobra, just....punch down. Seriously, we have seen a Hiken from him casually smash through the entire arena on Dressrosa and open up a hole to the underground cavern, just have him blow a hole in the floor, turn to flame and fly through it, then pick a direction and start busting through walls until he got outside (like Wapol did). The Gorosei clearly don't like showing their forms off in public, and Imu even more so wouldn't be able to follow, on TOP OF it being something Sabo could easily do himself but wouldn't have been able to do while carrying Cobra (because, you know......FIRE).
Covers all plotholes, and doesn't make any party look particularly bad. Also makes Sabo himself look clever and resourceful.
Instead Oda just.....cut away. Lmao.