Client screen going black after a queue

So, I was heading into a ranked game when my client went completely black and I was forced into a dodge. I still lost LP due to this (which I am not too frustrated about since I already have a low rank) but its just obnoxious that I had to sit there with no other options other than wait or close the client.

( Side note: Anyone know why this happened or how this happened, just so that I can potentially not have it happen again? )