Following timeline pulled from ADS-B data:
01:44:29Z DL1943 start TO roll
01:44:30Z AA106 at J-K-B intersection
01:44:39Z DL1943 40 kts
01:44:43Z AA106 entering 4L at J
01:44:47Z DL1943 79 kts
01:44:54Z AA106 at middle of 4L (interpolated between data points assuming steady taxi speed)
01:44:55Z DL1943 104 kts, max speed, at K3/K4, approx 2000 ft from J
01:44:58Z DL1943 85 kts
01:45:00Z DL1943 62 kts
01:45:05Z AA106 clear of 4L on J
01:45:05Z DL1943 33 kts at 31L/4L intersection
Curious to know if the DL crew rejected takeoff based on observed conflict or ATC direction. Or perhaps both events were simultaneous. Even at night, seems a 777 broadside at 2000 ft would be hard to miss as a takeoff hazard. I suspect there was the expected human brain delay as the DL crew convinced themselves that they were seeing the unexpected. Also curious how AA crew verified runway was clear to cross. At that point, landing lights from DL1943 should have been clearly visible (4500 ft away) as takeoff roll was in progress.