How can I set a drowning countdown?

This post contains spoilers

Here's my problem:

In Black Core Zone 1, you have a limited time to reach the end. Especifically around 1:24, since that point, a drowning countdown will start until you reach the end or die (1:35)

What I'm doing is changing Metal Sonic's path, and now he reaches before (at 1:17), but the countdown still appears at 1:24.

If someone knows how to set a drown countdown or change the one in BCZ1, please tell me

The space countdown is actually a separate gimmick from Metal Sonic's path. In BCZ1, it is done by a invisible FOF that stays outside the level until 1:24, where it's triggered to grow and then encompass the whole level, affecting all players in it.

This effect is achieved with the use of linedef executors, more precisely, a type 399 - Level Load trigger delayed by 1:24 minutes. Check these pages out to know how they are built in detail.
https://wiki.srb2.org/wiki/Linedef_executor
https://wiki.srb2.org/wiki/Linedef_executor_tutorial