Temple spell that boxes its targets inside the Khepri temple for at least an hour, like a dungeon timeshare pitch.
Rosetta explains that anyone under the Prospect spell is not allowed to leave the Temple of Khepri for at least an hour — Carl calls it the dungeon equivalent of going to a timeshare pitch. Once that hour is up, the affected can tell the temple's resident cleric to let them out.
That lockout is the raid's entire window. While Vinata's family is boxed up they cannot flee; the moment they are unboxed, any one of the three could run and escape, and the crawlers cannot risk that. Carl times the assault on Club Vanquisher to land inside the Prospect hour.
The timing mechanic that both traps the naga family and sets the deadline for Carl's raid.