That is SO sad! Our seedlings are our children!
I am very aware, at 66, that a careless step can result in a life changing accident within a second. I tripped over my strimmer last year and was in pain for AGES with a strained arm. And hauled a heavy roll of fencing around later that year and damaged my back for 3 weeks. I am now VERY cautious as I stagger around my 3 plots.
There was a thread here maybe a year or two ago about the dangers on allotments which would put a nervous person off for life, ranging from blinding yourself on a cane to cutting your feet off with a circular saw, stepping on a sharp nail and getting tetanus, and everything else you can possibly think of.
My experienced farming brother-in-law tried to clear a mowing machine and lost several fingers.
My great aunt broke her right arm and wrote us many illegible letters with her left hand.
If you only ever have had one arm, you have a life time to train yourself (my husband has one eye and was games captain at his school, which seems to matter to men), but if we lose a limb or sense later in life it is very hard.
A friend fell down her stairs very heavily 2 weeks ago, broke nothing, but admitted she felt very shaken and depressed and wondered if she was going to be one of many people of our age who suffered a shock and never quite recovered.
I don't want to be pessimistic - but we should all be careful while moving around our muddy, slippery allotments, full of tripping opportunities and difficult machinery (I am frightened of my own strimmer).