The remote [spoilers inside]

When one them gets shot and they reverse time with the remote. What's the explanation there? Is it just the film maker "messing" with us. Or, was it to illustrate no matter what they did. They weren't going to get out of this. The intruders are in control period. Or, is it something else entirely? Surely this has been talked about. I'm sorry if it's been discussed on here already. I couldn't find a thread that talked about it and I've always wondered what the intention was.