Suppose that I have a non-deterministic Turing Machine $M_1$ and its clone $M_2$. Given a string $x \in \Sigma^*$, it is possible that after $t_i$ seconds $M_1$ accepts $x$ and $M_2$ does not halt ? What happens if i run $M_2$ $2t_i$ seconds?
It is possible because the transition function $\delta_N$ is a partial function and the machines do random guesses, but it can't be that a machine reject and the other accept. If i run $M_2$ for $2_i$ seconds, the outcomes may be different.