So I am not quite sure if geas would still be in affect in a DMZ, or do the damage if the command is not followed.
It is quite confusing as some players say that it wouldn't, and others say it would. I can't really figure it out myself, because I am 50/50 on it.
O que acontece com o geas spell in a dead magic zone?
The 'rules' for Dead Magic Zones (DMZ) can be found in the Weird Locales1 table on page 109 of the Guia do Mestre:2
Dead magic zone (similar to an antimagic field)
So looking at campo antimagia:
Spells. Any active spell or other magical effect on a creature or an object in the sphere is suppressed while the creature or object is in it.
E como geas is a continuous spell (i.e. has a duration) it is suppressed while the creature is in the DMZ. Being suppressed is explained as
While an effect is suppressed, it doesn't function, but the time it spends suppressed counts against its duration.
so it should not force the command, nor deal any damage for failure to comply.
1: A set of some fantastical things a DM can put in the Wilderness of their world to make it more, or in this specific case less, magical.
2: If your DM is using different rules for DMZs I can't help you.