HELP PLEASE - I clicked on a "Critical Security Update" notification to hide it, but accidentally clicked install. The only thing that came up is "Install OS X 10.9.2" - and the only button is "Restart"

First of all, how can I just cancel this? What is going to happen when I restart? Will I be able to cancel after restarting?

Secondly, if I can't cancel, is this going to effect anything if I restart and it installs 10.9.2?

submitted by quasifandango

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