The pressure that can build up in an abscess is pretty amazing. While doing an I&D on a small abscess on a pt's foot I was surprised at how far pus can travel. The stream of fluid that came out of the skin after putting in the lidocaine should have been a warning to me, but I ignored it. As I cut through the skin with the scalpel I released the pressure and out came a bunch of fluid and pus. Unfortunately, I was standing right in the line of fire as it sprayed all over the front of me. Thankfully the patient felt better so I went and changed.