I'm guessing perhaps he wasn't sure he got the first decision right too, and didn't want to give both decisions to the same team.
Would've been funny if Tomkins had persuaded Friend to give another penalty with his 'I didn't touch the ball' stupidity.
It was a clear penalty. Murray got the ball, then tapped it a few yards further with his right leg, and Tomkins ran into him, making it impossible for Glenn's left leg to catch up with his right. It was a clear foul in the box.