I want to publicly and sincerely apologize for that comment. I didn't mean to imply that you missed a clue that could have prevented this.I feel like I generally read the room pretty well
You have a good handle on things. I don't see it as a case of having "let down your guard". Roland wasn't picking on Isa and she wasn't terrorizing him. You didn't leave them together unsupervised.
I agree with @BrianB 's advice. Hopefully Isa can learn Roland isn't a threat.