Yeah it's not good is it, esp the first moments when you realise what's about to happen, think I'll wear the HR monitor one day just so I can see the massive spike...
I had a near clipless moment, in front of a queue of cars and lots of spectators on Monday. Couldn't get left foot out, ending up kicking out so hard to release it I started leaning to my right...... AHHHH saved at the last second but not without bouncing around a bit making a fool of myself. Might upload the video at some point as you could see my shadow all the way through it lol.
Worse thing is when you've clipped in without realising it. I often silently clip in when in stop-start traffic so I've gotten into a habit of checking every now and then.