Sorry, didn't realize you had missed all of my earlier posts on this.
If a PC hides, then quickly moves from cover to cover on their turn, they continue to benefit from the hide action.
If a PC hides, then slips out from an empty room, behind a guard patrol, and down a different hallway, they continue to benefit from the hide action.
If a PC hides, then scrambles up to cling to the ceiling as a guard patrol rounds the corner and passes under them, they continue to benefit from the hide action.
If a PC hides, then rushes out of cover to stab a guard in the back, then they lose the benefits of the hide action after their attack.
If a PC hides, then bursts out of cover in front of a guard, makes funny faces at them, flips them the double bird, then darts down a hallway... they do not continue to have the benefits of the hide action unless they make a new stealth check.