Wait for response?

I'm using slack to post messages and I'd love to be able to respond. The slack node has both get and set so I can read messages posted so I just need to figure out how to post, wait n seconds for a response and process that. I was thinking of storing the most recent incoming message in a flow variable and clearing that every 30 seconds. Then, after I post a message to slack keep checking that variable every 2 seconds for a viable response and if it's there continue if not timeout and reset. Is there a better way?

The in node should just deliver a message whenever one arrives so you should not have to poll/query all the time.