Session 4 would likely begin with Vila experiencing the effects of the swamp plague, suffering one level of exhaustion, adding to the exhaustion she already had from her frenzied rage. Good Morning would have cast Find Familiar and summoned a hawk familiar, which they intended to send up the hole in the ceiling where they heard the giant.
The party would then need to decide which area to explore next. They had several options remaining from the end of the previous session. One possibility is returning to the room with the mysteriously glowing well and the hole in the ceiling to investigate the giant further, perhaps attempting to send Good Morning's new hawk familiar up to gather information. However, their previous attempt at communication yielded no further response.
Another option would be to continue exploring the doors in the room with the model city. They could proceed clockwise as Yor Eye suggested previously. This would lead them to the passage with the double bronze doors bearing the face of the jaguar god and the carved warriors holding halberds that sparked with electricity. Good Morning had a dangerous encounter with these guardians, getting shocked and paralyzed. The party would need to find a safer way to bypass them, perhaps by crawling underneath or finding a way to disable them.
Beyond that door, they found a room with a fetid smell, human skins on the wall, a statue adorned with skulls surrounded by burning coals, and a silent panther that suddenly became hostile towards Vila. They quickly dispatched the panther, but the room itself with the glowing well and the blackened mirror remained largely unexplored. They might choose to investigate these features further, although they were initially wary of the glowing liquid in the well. Yor Eye did examine the mirror and found it to be normal.
The party also acquired a Wand of Lightning Bolts, which they might decide to utilize in any upcoming combat encounters. Vila now possesses the Luck Stone, granting her a +1 bonus to ability checks and saving throws.
Considering the party's cautious approach after encountering several traps, they would likely proceed methodically, potentially using Good Morning's hawk familiar to scout ahead where possible. The mystery of the giant in the ceiling and the dangers behind the jaguar god's door would likely be high on their list of priorities for exploration in session 4.