If I roll one $6$ sided die, the chances of getting one number, say $6$, is $1/6$ or $16.6\%$. If I roll $2$ dice simultaneously, then the probability of rolling that number twice is $1/36$ or $2.7\% (1/6 \times 1/6)$.
What if I have this situation: I roll a die, and if I get a $6$, then I'll roll again. What are the chances of me getting a $6$ the second time? I think it's also $1/36$, but the difference is that I make the second roll if I get a $6$ the first time. If I roll $2$ dice simultaneously, let's say I differentiate them as the first and second die, the first die can be any number other than $6$ while the second die still rolls. Is it still the same?
Is not getting the $6$ the first roll, and not rolling the second die, and rolling two dice simultaneously and not getting two $6$'s the same level of failure in terms of probability? (even if $1$ die rolls a $6$ the other doesn't? Say I get a $6$ on the second die but not the first).