ويعتبر حال العبد في ذلك الجزء
The person's condition in that final portion is taken into account.
A person's status may change during a prayer period—for example from travel to residence or residence to travel. Under the source's analysis, the relevant final portion can determine the form of the still-unperformed obligation.
This is not an encouragement to postpone prayer. It is an analytical rule explaining which personal status governs when a valid obligation remains unperformed and the person's situation changes.