I didn't think of it at the time.
what if someone takes away the ladder while we are down there
It would have been an embarrassing call to the emergency services. It's similar with a window.
what if they board it up while I'm inside
I could use my fabled 'Kung Fu skills' to sort this little matter out, of course!
The fear as well that if someone did do something like that and you went to phone the emergency services and you couldn't get a signal. Yikes!!!!
But that is close is when the Kung Fu skills would be pulled out of the bag :0D
In that case, I would need to drink out of that old bottle of Sprite and survive on pigeon shit until another explorer happened to pass by!
The explorer would pass by and you would be this strange and filthy half man, half pigeon thing with an old sleeping bag wrapped round you.
They might not stop to help :0D