If you were so inclined, you could make a quick visit the ruins at Panama Viejo. At 3 pm, it would be very hot and humid and possibly raining. The ruins are not that interesting, especially compared to other colonial sites, but the museums (with a/c) there might interest you. Google "Museum Plaza Mayor" and "centro de visitantes panama viejo". Traffic wouldn't be a problem before 4:30, 15 minutes both ways in an Uber. You couldn't spend more than an hour at the site though. This would be for risk-tolerant travelers eager to check a box off their list. Most of that gold the spaniards sacked out of Peru that you'll learn about in Lima passed through Panama Viejo on its way back to Europe.