The squiggly lines do more than just show you the route your dudes will take. By clicking the points on the route, you'll be taken to that point in the timeline. This is very useful for synchronizing actions. It's even more important when your crew has to clear several rooms in sequence. You definitely don't want some dude to burst into the room solo simply because the one with the flashbang was only meant to throw it in 3 seconds later.
