Per Wikipedia, here is the timeline that morning. Shooter was only outside hotel for 5 minutes before shooting.
- 5:34 a.m. – Suspect leaves the hostel, and rides an e-bike to Midtown.
- 6:15 a.m. – Suspect seen leaving the 57th Street F Train subway stop.[48]
- 6:17 a.m. – Suspect buys coffee, water, and granola bars at a Starbucks café (at 1380 6th Ave) two blocks away from the New York Hilton Midtown hotel, discarding the coffee cup and water bottle.[48][49][34]
- 6:30 a.m. – Surveillance footage captures the suspect walking while talking on the phone.[29]
- 6:39 a.m. – Suspect arrives in front of the New York Hilton Midtown hotel and waits for several minutes.[34][49]
- 6:40 a.m. – Thompson leaves the Marriott hotel (at 151 W 54th St) he stayed at the prior night, heading toward the New York Hilton Midtown hotel.[32]
- 6:44 a.m. – Thompson walks along the sidewalk toward the New York Hilton Midtown hotel and the assailant shoots him multiple times, racking his pistol after it appeared to jam; the suspect immediately flees northbound via a pedestrian walkway.
Someone had to be notifying him the victim was leaving the hotel. Perhaps even the same someone that caused him to leave the hotel unescorted.