Where's this bug

Odds of anyone reading this are probably very small but one of the developers wrote this about Ironsword:
"The concept of testers sending us bug reports was completely alien, but we got with the programme and tried to change our mindset. I think we were mostly successful. Actually, come to think of it, I’m sure there are a few odd collision bugs in Ironsword still. Not bugs as such, just ‘gaps’ in the collision data where it’s possible to jump through the invisible walls and fall off the screen, if you keep jumping at particular walls from odd angles for long enough. We spent ages fixing those, but I’m sure a few slipped through the net."

Let me recopy the key passage:
Not bugs as such, just ‘gaps’ in the collision data where it’s possible to jump through the invisible walls and fall off the screen, if you keep jumping at particular walls from odd angles for long enough

Where is it possible in Ironsword to fall off the screen? Looks like a new bug to figure out for people who like to discover things.