I don't think the OP is beating himself up over retreating, which was the right way to handle the situation, but rather he is simply pointing out that leaving his EDC at home could have been a costly mistake had things gone differently.
Gotcha. Although I think the holster location might have been an issue for this compatriot, and he can now revise, I'd proffer worrying about only having the BUG gun is misplaced. If one has a BUG gun, one should be able to rely on it.
Ankle holsters are like other holsters, outfit and operator preference decide whats best for them. As I live in "sinners go to Hell, REAL sinners go to Texas" Texas, shorts are standard issue uniform half the year and an ankle holster looks a little out of place...