Bentham actually stops and moves across into Houston's path, I think it was accidental particularly since his eyes were on the ball. We often see players from the defending team stepping across chaser's paths and colliding with them and it looked similar to that.
I suppose the problem is that the referees are obviously not expecting or braced for any contact so when it happens it is more likely to cause injury.
2 matches seems harsh, he will be a big miss for Widnes he's started the season well, I reckon they will be going after Leeds on Sunday as well with them coming off the back of the WCC and losing him takes a fair bit away from their pack.