Well according to Sir Mark Rowley, the Commissioner of the Metropolitan Police, the officers were justified in what they did and he commends the unarmed officers and the member of the public (believed to a member of the Jewish security team) for their bravery.
As for your crass remark about a "teeny weeny" knife, that knife put two grown men in hospital, men who were just going about their daily lives and who, no doubt, will be dealing with the trauma of being stabbed for a very, very long time; as will be the case with the first victim, the Muslim man.
In addition, Essa Suleiman has been charged with three counts of attempted murder because short-bladed knives can cause fatal injuries. I'm amazed this needs to be pointed out to you.