So. Uberuce. You idiot.
Next time you think 'hrm...this isn't really working, I'll give up and walk it once I'm at the end of the road' what you should do is pull over immediately and walk it. Otherwise you'll catch your foot on the edge of box you were carrying, just like you were worried about doing, and elbow-drop the pavement. Then you'll not get home for another two and half hours and I bet your elbow is going to start hurting properly by tomorrow morning.
You'll also give that lovely woman who'd just overtaken you the fright of her life thinking she'd somehow caused it, and spend ten minutes persuading her that you're only slightly injured and don't need to be driven home. Box of chocolates and a replacement big plaster by Monday, or you're for it. And don't even think about stealing one out the work supply. In fact you're going to link this thread to your boss right now so she keeps the first aid tin out your idiot hands. yes, I said tin. It's plastic, I just like the word tin.
On the plus side, I had a lovely chat with the nurse in the Infirmary about the relative merits of SPDs. He reckons they probably exacerbate minor accidents but he'd never go back to flats either.
Carrying a Big Thing Home and Riding Sorta Onehanded, Even on a Quiet Flat Street And When Riding a Fixie And Therefore Not Needing Left Hand to Brake is now on the list of Things I Should Have Known Not to Do In The First Place And Now Definitely Won't Do Again
Two stitches, some glue and some steristrips. The Cow of Wilma need not worry about losing his CCE Elbow Scar crown.