So the display and sound drops off for one-half second. And it is because hdmi cable is set to transmit both sound and picture.
In my opinion, the game continues playing in the computer but the hdmi cable momentarily cuts out. So you cannot see and hear anything. The TV set does not turn off.
Can you reseat hdmi cable at both ends (computer and TV set) and/or try another hdmi cable ? Broken wires in the cable or loose fit might cause this because sound waves may cause shaking of the cable during high levels causing cable to lose momentary connectivity.
Hope this helps.