It is ultimately not seen in the film.
Relationship with the Commando Elite humans:
Sentry is on their side at all times, is their supervisor, babysitter and worries about them at all times.
Sentry cares about all the Commando Elite people at all times, it is their guardian, bodyguard and is very protective of its Commando Elite human best friends at all times, heavily guarding and securing them at all times when it is summoned by them.
It never lets them out of its sight, observes and keeps a robotic eye on them at all times.
It also prevents any Commando Elite human sneakiness, like them trying to sneak away from it.
Relationship with the Commando Elite Robots:
Sentry is friends with its self, Bipod, Mortar though never looks after Bipod or Mortar, looks after it self without anyone`s assist.
Sentry can be summoned by Major Chip Hazard in the 2 player mode in the locations:
- Spirit Bog.
- Hall Of Patriots.
Sentry is summoned in some of the 1 player mode levels too.
- Major Chip Hazard.
- Other Sentry robots that are the same as it.
- Bipod, though does not look after Bipod.
- Mortar, though does not look afer Mortar.