I think some of the on-screen instructions for Workout 2 need tweaking.
For the 4th sprint, with the 30 second easy spin beforehand, the on-screen instructions aren’t clear that there’s an extra 30 second period, and seem to indicate the hard effort starts earlier than it really does.
The instructions with 30 seconds left of the 3 minute rest say something like “in 30 seconds we’re going to do the one that really counts”; but actually that interval is in a minute’s time. You can see where I started sprinting and then realised it wasn’t the interval:
It’s not just me, either. I mentioned this to a friend, and he did exactly the same thing. Here’s a trace he sent me:
[oops that was my image again, I’ll try and find his]
The same “oops! too early” mini-sprint just before the 4th intended one.
These instructions could be modified slightly to make it clearer. I think they subsequent similar sprints are better described.