I disagree. I don’t know that how much time passed between when one might argue that the police should have left and when they heard the glass breaking. It could have been seconds. At most, it was probably minutes. I have no problem if the police hesitated in leaving from outside the home, wanting to be in position if help were needed. The sound of glass breaking could create a reasonable belief that an assault is taking place inside and that their help was needed.When both parties verbally told them they were safe that ended the officers leeway to enter.
They should have been gone long before they "heard glass break".Assuming they did.
Still, I don’t see obstruction here. There is no moral duty (and, therefore, should be no legal duty) to assist the police in making a mistake.