I work at lambda, and my team would be the one to engage with OP, it most likely would have been me actually to investigate this.
The fact that support didn’t engage us seems odd as we have gotten engaged for far more silly stuff.
However, in this case you should have awaited for the response from event emitter.
The lambda execution model clearly does not allow you to run things past the response as execution is frozen by the sandbox / virtualization software. From there, you’ve most likely caused a timeout when issuing the request.