River and Rafael moved the second Travis was attacked by someone on his side. Neither cared why the man was betraying Travis. All that mattered was Travis not having the gun pointed at the two of them.
The sound of a bullet being fired was heard followed by Solomon falling back. There was a pain in his chest from Travis shooting him with the gun, but he tried his best to hold onto the weapon so the knights would get Travis.
Solomon was shot once more in an attempt to get him to let go of the gun before River could reach Travis. Solomon felt weak as he experienced a new type of pain. He continued to struggle with Travis for the gun with what strength he had left as this was his way of avenging Mack and all the others he took to Travis's study to be killed.