Hi Pavlina,
Though this question seems quiet old, but can be useful to other forum users
If One of the operator approves the request and the other rejects, both the branches will execute and the workflow will not wait on the approval activity for all the responses, it will be in started state and will keep execution in progress as soon as it gets its first response (approval/rejection).
If approval comes first, the yes branch will continue the execution further and as soon as rejection comes, the no branch will also start execution and vice versa.
You can see this in below screenshot, as soon as the no response came from an operator, the workflow started running and again yes response came from other user and the yes branch started its execution.

Hope this helps.