Hmm, depending on the height the SPAM was dropped from, it would reach a speed that would easily knock you out if it hit your helmet. Then you you would be laying on the ground and a much easier target. Perhaps if you had Captain America’s shield for cover, you might be alright.
But a shield is much harder to fit in a handbag. I think Lydia’s advice to keep moving is more practical. A moving target is harder to hit. And running won’t mess up your hairdo as badly as a helmet.
Although, if you had a electromagnetic metal-repelling helmet that created a safe zone repelling field around you, you could laugh at the falling SPAM and continue to enjoy your walk.