I don’t have one of those Amazon things but from OP’s phrasing I’m guessing that it’s possible to interrupt Alexa even while it’s talking. That would imply this

I don’t have one of those Amazon things but from OP’s phrasing I’m guessing that it’s possible to interrupt Alexa even while it’s talking. That would imply this lock isn’t in place. I’m guessing that the device just cancels out the output waveform from the input.