When travelling through vortex you can encounter random anomalies. You have a maximum 10 seconds to hit a combination of button's before tardis take's critical Damage.
Time Ram: When the Tardis merge's with it's past or future, in the show this could destroy the tardis, so you know what happen's when you fail. Tardis blow's up along with you and a big chunk of the know universe.
Blackhole: (Don't ask me why you would find one in the vortex) Because this is a rare/ very danngerous anomaly, you get two chance's to escape. One when you needed to escape the intense gravity which if failed will drop tardis health to 20% and the second one to avoid getting sucked in that if failed will drop tardis health to 0% which will cause an emergency landing.