So I was thinking, shouldn't the HACKNET terminal be -kind of- far away from the zone? Was OP fighting last night as Hacknet fighter and, well, I tried my best to cover many of the possible entrances my enemy could come from, without success.
So I'm thinking either move the Terminal to a more suitable spot or make it so there is some kind of loading process to go through when clicking it, or kill a NPC that servers as security and which can only be damaged once the 3rd layer went down.
(The first solution seems the easier to do, as it doesn't require a lot of coding process + it doesn't make everyone to be a HN char to be able to do the 4th layer)