Visiting my FIL in the hospital, post-op Day 1 after spinal fusion. As always, I'm doing my best to fly under the radar and not announce by word or action that I'm a nurse. It's apparent that we have an orientee tonight, as 2 nurses always enter and leave at the same time and one is obviously instructing the other. Preceptor explains rationale behind d/c'ing IV fluids and PCA. Instructs orientee to hep lock the IV, then leaves the room. I'm looking the other way when out of the corner of my eye, I see a blur of blue scrubs flying out of the room and hear "I need HELP in here!" shouted into the hallway. My eyes fly to my FIL, who remains A&O, eyes wide, looking at me as if to say "Am I dying or what?" I look to his IV site, where the blood is pouring out so fast that it could very well have been arterial, exept for the color and the lack of pulsation. By the time I jumped to the bedside, the orientee was back, applying pressure to something (not sure what) since blood continued to pour out. I reached across the bed and quickly crimped the tubing and stopped the blood flow. The orientee actually looked at me as if to say "WTH are you doing?" I just quietly said "if you'll use the clamp on the tubing, the blood will stop running out." She finally found the clamp and used it.Lesson #1: Never, EVER run into the hall screaming "I Need HELP!"Lesson #2: Never walk/run away from an IV site that is draining blood onto the patient. One way or another, clamp that sucker off.That is all.