Note: The fastest way to visit Crondis is to teleport to Menaphos, run west to the shifting tombs entrance in the Imperial district, right-click the entrance and select Ports, and then run west to the Portmaster.
Collect 16 croc ices (buy at least 24), then return to Crondis as fast as possible without teleporting. You can use the flying carpet at Nardah to travel to Menaphos, and then use the shifting tombs entrance at the Worker district to travel quickly to the Ports district.
Talk to Crondis. Any chat option, except 1 for all dialogue boxes.
Kill Ukunduka (stay out of melee distance or use Saradomin Brews).