Patch 5.3 crashing computer multiple times - OS X

I have never had League crash before the way it just has. In one game, at 59mins, League simply froze. (specifically, I was stunned by Veig and trying to use cleanse and Intervention, but I doubt that is relevant as explained later). I was unable to command-tab out, or to open the force quit menu, and hold the power button to restart my computer. In the following game, I was chasing a Panth for a kill when League once again froze completely. After rebooting, I immediately opened League again and found the League logo stuck on my desktop. Opening it again to have it kill the previous instance, the force quit menu, and activity monitor all failed to remove that league logo from the middle of my screen or to start the game. I then restarted via the apple menu and watched with amusement as the League menu stayed on my screen all the way through the logout process until my screen went black.

This is very clearly an issue, and it's never happened before 5.3. I did not have the patching issue some have had. I am on a Macbook Air 2012 with Mountain Lion.

In another game now, will report if any further crashes occur.