Irishman
We watch as Wallace and his men speak with Stephen the Irishman. He appears completely out of his mind and potentially dangerous to Wallace and his men as it's uncertain about his loyalty. Stephen rushes Wallace with his sword and William believes the Irishman is trying to kill him, when in fact he's protecting him from a murderous traitor by throwing his sword into the attacker on Wallace's other side. The imagery reveals that in times of war it is hard to distinguish who to trust, and those on our side may end up surprising us.
Murron
William is being tortured to by the English. Just before he is decapitated, he sees Murron, his wife, walking through the crowd. She was murdered by the English and this imagery represents his going home to be with his bride - something he has longed for since her death.
Wallace's Sword
We see Wallace's sword plunged into the earth during the final scene of the film. It is put there by Robert, who is now King of Scotland. Robert is meant to submit to the English to be under their rule. But instead he plunges Wallace's sword into the earth and leads his Scotsmen to victory over the English. The imagery of the sword represents the lasting effect of Wallace's fight for freedom.
Freedom
Wallace is tortured by the English in order to get him to pledge his allegiance to the monarch. But through the torture he will not submit Scotland to English rule, he instead cries, "Freedom!" before being beheaded upon a cross of wood which he is tied upon. The imagery relates his sacrifice to a greater cause - that his life matters little if he isn't willing to die for what he believes in. This makes the imagery of him praying for strength from God before hand so powerful, and his suffering is connected to Christ as Wallace lies upon a cross.
