Basically a global lock is just a full chill and of course is worse than just a partial chill.
Global lock is where the DTCC denies ALL services and the "chill" label is designating that only some of their services are denied such as allowing only "trade for trade" and not allow the company like THRA in the Net Settlement System which can make some brokers not want to trade it or charge more for it.
"I stickied this one to show that the CEO calls it a LOCK and not a CHILL as some have tried to call it."