I live in London wallpaper afternoon Jesse has been swindled and beaten up by psychopathic gangster Tuco. Walt confronts Tuco in his office, offering him more crystals but insisting on being paid immediately. Tuco starts to get nasty but Walt has a plan. The bag of meth crystals he has just given Tuco were in fact "fulminate of mercury". He throws a crystal on the ground which detonates, creating an almighty explosion. We see Walt walking victoriously from the smoking remains, clutching his bag of money. But could a small crystal really do so much damage?