Doohickey fell out of ignition cylinder lock

[dmjlambert]

Can you help me temp fix my ignition cylinder lock? I had sudden failure of the lock, I couldn't turn the key without doing some serious wiggling. So I removed it to have a look. I suppose I need a new cylinder, but I can't get one today. The cylinder has a little bar that moves up and down depending on whether the key is in it, and I suppose that's what makes it lock. The bar has 2 doohickeys, one on each end. You can see in this picture it appears 1 has fallen out. What holds that in place? Is it just pressed in, or do I need to do something to make it fit and stay?