Problem: Need to haul groceries home from the store. Rides a BMX bike that cannot accept panniers. Doesn't want to crush the bread. Needs to haul bottled water to last a few days.

Desired solution: Take care of this grocery shopping errand by bike. But this desire doesn't negate the problems expressed above.

Solution: Hire an Uber for a few bucks. Once you're done with your shopping, and the groceries are safely stowed in the fridge, go out and tool around some more on your BMX bike.

(Maybe this whole thread is just a joke. Who uses their BMX bike for grocery shopping and is afraid of crushed bread and cannot do without bottled water for a few days?)