Not to harp on you, unbreakable but I'll chime in with these guys.
It's really important to kill them all! You just plain out, never know, and it's not worth it to take chances.
One escapee..ah probably no harm. Two or three, not too big of a deal (although I'd argue to take it seriously).
But a whole colony? You're practically daring them! And giving them a great chance for the summer too!
I keep a bucket of bleach next to my container. When I pull out old collard greens and such that could have hiding nymphs in it - into the bleach. Nothing leaves the colony without being eaten, stomped, or drowned.
It's a good habit to keep.