I think you are very lucky if you manage to train inside all year!
This is the only bit I disagree with you about
as given the chance & choice we will train outside.
We are very lucky as one of the clubs we go to has the choice of fields & also an indoor arena (where trainers are quite adequate not to slip on the flooring) where we can train if the weather conditions are poor - like last Sunday when it was quite blustery. This class is held for people wanting to compete this year.
Whereas the other club I attend will cancel classes if the weather is really bad as the majority of people in that class are simply there for fun, have no intention of competing & possibly dont have the experience & TBH I dont think I could call it fun running in the rain
It is not recommended to run an agility course on wet/slippy ground - as you have discovered, handlers can slip - but so can dogs, and can be badly injured
I know a lot of classes are held outside in all weathers - but it isn't considered to be responsible by experienced trainers/handlers
I have slipped on damp grass, after a spring shower, when I ran Molo in a "fun" class, so I know how easy it is to do
I guess you learnt by your irresponsible mistake then
& unlike the rest of us wont be needing any footwear with grip
ETA:
Getting back to the topic: Before posting this thread I did go into a large local sports shop & ask if they had any hockey shoes & the young assistant looked at me as though I'd landed from another planet & just said "err ladies shoes are over there"
At least now I have an idea of what I'm looking for I should be able to find something & maybe I'll be able to run that bit faster