The first time watching this scene in the cinema it didnt even cross my mind, im sure many others didnt aswell so its feasable to think the characters in the film didnt think of it either, especially considering the stress they were under, they only had one chance where as we get to watch the films over and over again and can come up with different ways to handle the scenarios, for those of you who thought it of it first time watching u r really observant and clear headed   
 As other people have mentioned, being electrocuted like that probably effected the blood in someway, has anyone here studied this kind of thing?