How do we change a Grand Canyon hiking plan when one friend calls it giving up?

People, dialogue, plans and prices are fictional; this is not a live weather report.

‘We drove six hours for a walk, not another viewpoint,’ Marcus says. His friend Claire has just questioned their proposed 11 a.m. start below the Grand Canyon rim during an imagined summer visit. They are still at their accommodation, making the next day's plan.

Their motel cost $164, and Marcus has talked about this hike for months. Claire had agreed to a walk without looking closely at the descent and return. She now reads the National Park Service's [summer hiking guidance](https://www.nps.gov/grca/planyourvisit/hike-smart.htm), which advises planning to avoid hiking between 10 a.m. and 4 p.m. and warns that eating and drinking correctly do not remove the danger of the hottest hours.

Marcus suggests carrying more water and going anyway. Claire does not want that plan. The third friend, Dev, would consider a different route or time if current park advice supports it, but nobody has checked current trail conditions or water availability.

They can still spend the day at the canyon, yet Marcus feels the particular trip he wanted is disappearing. How would you change tomorrow's plan without letting the motel bill or his disappointment decide the safety question? What can the others offer while keeping Claire's refusal clear?