Where to find Sentinel in Jailbreak?

Excuse me, could you please clarify for me where exactly I might be able to locate Sentinel within the Jailbreak environment? I've been searching high and low for him but seem to be coming up empty-handed. Is there a specific area or location within the game that I should be focusing my search on? Any tips or tricks you could share would be greatly appreciated. Thank you in advance for your help.