Scenario 1)

I have a lvl 4 sorceress. I roll 4 dice simultaneously - 2, 2, 4, 6.

I have rolled a double, so I can swap one. I swap one of the 2's for a 3.

*I then swap the other 2 for 0.*So now I have 0, 3, 4, 6.

Scenario 2)

I have a lvl 4 sorceress. I roll 4 dice simultaneously - 2, 2, 4, 6.

I swap one of the 2's for 3. I am then stuck with the other '2'. So now I have 2, 3, 4, 6.

*I could have swapped one of the 2's for the - spell, or I could now swap the 4 or the 6 for the 0 spell, but I am stuck with one of the 2's.*

I am fairly sure Scenario 2 is the correct but I want to make sure. If possible, please explain why Scenario 2 is correct.