Stanton falls over and lands in a pile of blood on the floor as he is following the pipes. In every shot after that, there is no blood on him or his clothes.
When Connie goes to get Toni from the gas chamber to tell her she found out that she was being tricked. After Connie checks to see if Toni is breathing and realizes that she is dead, you can see that Toni is actually breathing heavily and rapidly.