Quote:
511. End of Combat Step
511.1. First, all “at end of combat” abilities trigger and go on the stack. (See rule 603, “Handling Triggered Abilities.”)
511.2. Second, the active player gets priority. Players may cast spells and activate abilities.
511.3. As soon as the end of combat step ends, all creatures and planeswalkers (including those that are phased out) are removed from combat. After the end of combat step ends, the combat phase is over and the postcombat main phase begins (see rule 505).
So you should be able to activate the maze after damage resolves, because removing them from combat is the last action and each player gets priority before.