He is left in charge of monitoring Skinny Malone's prisoner Nick Valentine, and appears to be the boss' right hand man judging by his orders. Dino guards the Vault 114 overseer's office, which has been converted by the gang into a prison cell, taunting Valentine.
Unlikely Valentine - Dino guards Nick Valentine's jail cell. The detective uses his speech skills to convince Dino that Skinny Malone is planning to have him killed due to believing him to be a card cheat, causing Dino to run off in a panic. He holds the key to the overseer's office in which Nick is being held captive.
After finishing his conversation with Nick Valentine, a panicked Dino will run off to try and "smooth things over" with Skinny Malone. His path takes him past the entrance to the Vault 114 common area, where he will most likely spot and attack the Sole Survivor. If the Survivor manages to avoid being detected by him, Dino will run downstairs to the basement shower area. He will be confronted here later on as Nick and the Sole Survivor pass through on their way out of the vault.
If one initially avoids Dino instead of fighting him and hacks the terminal lock to Nick's room instead, the dialogue from Nick and the Triggermen who appear shortly after Nick is released will all still assume that Dino was killed by the Sole Survivor.
Although Dino is initially marked as green (non-hostile) in the HUD, he will immediately turn hostile upon spotting the Sole Survivor and attack.
Like most single-map NPC enemies, Dino's stats are generated from one of a number of predefined presets based on the player character's current level. Dino always spawns one tier higher than the highest level Triggerman that can normally appear at the Sole Survivor's current level (i.e. if level 25 Triggermen spawn when entering Park Street station and Vault 114, Dino will spawn with level 37 Triggerman stats). This makes him tougher than the average Triggerman, with stats identical to Skinny Malone.