In Live Free or Die Hard (Die Hard 4.0), Thomas Gabriel outsourced the initial stages of his plan to black hat hackers. When their work was done Thomas's team who are parked outside a hacker's place causes the hacker's PC to lock up. In response the hacker presses CtrlAltDelete, which sets off a bomb. We see that when the "glitch" occurs there's a light in the PC hardware that changes.
But why do the hackers have explosives in their PCs? One possibility could be that the PCs they used was given to them by Thomas but
- It seems strange to me that a hacker (and one who's being watched by the FBI) wouldn't pull apart a PC they were given for free from a stranger and not notice the packs of C4 inside (if they even accepted something like that)
- The computers seem to have been customized, like how Matt had his chat with Warlock which I assume isn't a standard chat system (given that Matt had to hack a satellite to see if Warlock was still online). That would mean that the hackers had the PCs for some time to get them customized for their use,
So how/why do the hackers have explosives in their PCs?