Zoek is Dutch for track (command used on Belgian Malinois).
ISR is short for Intelligence Surveillance and Reconnaissance.
Kinetic op, or Kinetic operations, is just another phrase for lethal operations. That is, the killing of an enemy as oppose to disarming or taking away the ability to fight, such as jamming the communication equipment of a hostile party.
An outstation is a station or post in a remote position ; a branch of an organization situated at some distance from its headquarters ; an outpost.
What we're seeing Clay undergo in this episode is the final phase of his candidacy initiation is SERE training (Survival Evasion Resistance Escape). It involves survival training and techniques for escaping from captivity. It also includes techniques for dealing with torture as depicted here.