Her flashback shows that she didn't, and she tells Richard that her patient needed her. After seeing Alex run in and start the procedure, she takes a deep breath and goes into Evan's room. Sloan and Arizona watch as she sits next to the crying teenager and starts telling him about the rain, her friendly, perky demeanor back. She starts to talk to him about the rain and how beautiful things are after it stops, and eventually he is able to stop crying and look at her, so she beams. She finishes by telling Richard that Alex seemed to have the situation at Cathy's bed under control.
Reed, however, thinks he was totally out of control, and describes him as pale and shaky. There's a Cathy-view cam of Alex leaning over her, and he's comically sweaty and nervous. Seriously, the nerves needed to be dialed back a little bit here to be convincing because this looks like a cartoon or a spoof of some sort. As Reed freaks out because there are no landmarks for Alex to know where he's going in, Alex sprays iodine on her neck and starts mumbling to himself, "Hit the carotid," over and over. When Reed gives this detail to the panel, they all look Very Concerned, and we cut back to Alex, well, cutting into Cathy's neck and feeling around.
Before we see what happens, Richard asks Alex if he gave blood. Alex is in an especially combative mood and seems to not get what this has to do with anything. Richard tells him about the "pale and shaky" claims and points out that one guy passed out, but Alex won't bite, and tells them that he regularly gives blood, and a bunch of people gave blood that day. "Just because some dumbass didn't eat a cookie..." Richard sees what Alex is doing and finally asks him specifically if he gave blood that day. We flash back to a shot of him scowling in the chair while Avery and Charles talk about him, and then after a moment, he gives his answer to Richard: "No." I will confess I was totally duped; I thought Alex was lying and was going to be on the chopping block or something because his Izzie problems clouded any bit of good judgment he had left. I actually said, "Oh, ALEX," at the TV.
Then we see how it actually played out: He's in the chair and the nurse is rubbing his arm while he talks on his cell phone with Izzie's mom. It sounds like Izzie either isn't there or her mom is lying, and of course this is right when the boys turn to around to call him a douche. No wonder he's got an even bigger scowl than usual. Everyone's pagers go off, and it turns out that the nurse was standing with the needle, just about to stick Alex. He tells her to wait and then rips off the blood pressure cuff and heads to the ER, no blood having been donated. Phew.