Tunnels are perhaps the only "no stopping" situation where there is nowhere to pull over. Luckily, tunnels are also the absolute simplest self-driving scenario.

Tunnels have to kept clear of obstacles. If an SDC would have to stop, so would a human-driven car.

For the others, stopped cars are very common.

So long as "bail to a human" doesn't take long e.g. 5 seconds to connect to an operator, it might not need to pull aside at all.