The Doctor starts outside the TARDIS.
The Doctor can only Enter the TARDIS if he exited the TARDIS before.

How can the doctor exit before entering if he starts outside?

Kata design issue: there are upper and lower limits to DateTime dates, which is start of year 0001 to end of year 9999. Time travel interval will hit these limits very quickly.

If the Doctor regenerates inside the TARDIS, the TARDIS will travel (in months) the Factorial of their regeneration number.

This is even worse: the maximum DateTime range only contains 120000 months, which is exceeded when regeneration number reaches 9 (362880 months). Once it reaches 13 it doesn't even fit into an int.

MeetMaster behaviour is not tested; a solution that do not implement this will still pass the tests.

There are still no random tests.

Description does not specify that Doctor starts at regeneration 1.

Missing specs:

• Does Run without Attack increase regeneration?
• When does Attack / Run regeneration reset? The actual tests expect every time Run happens after Attack.

If the Doctor regenerates inside the TARDIS, the TARDIS will travel (in months) the Factorial of their regeneration number.

Is this a forward or a backward travel?

If the Doctor meets the Master, the Master will stole the next regeneration of the Doctor, so the next time the Doctor regenerates they will have to skip the next iteration.

This part needs clarification. What does "skip the next iteration" mean?

There is a fixed test in sample tests with invalid date pattern (2023-10-07 15:00:00).

There are several incorrect sample tests as well. Most likely the sample tests are outdated.

Why is the input param param object[] args when it clearly should be string date, params Action[] actions?