Why wasn't Miles Dyson disarmed?

In Terminator 2, they break into Miles Dyson's workplace (can't remember the name of it) and begin to plant explosives in order to destroy all the work he had been doing

When the police get to the scene a small team eventually break into the building and work their way upstairs. Arnie and the guys escape leaving the badly injured Miles Dyson with the detonator for the explosives.

When the team of police find Dyson, he is sat up against a counter of some sort holding a heavy weight above the detonator trigger. The policemen see this and after Dyson says, "I don't know how much longer I can hold this", the officer in charge rather assertively says "MOVE OUT! MOVE OUT!" and they try and make their exit.

They're clearly not fast enough as the building blows up a few seconds (if that) later. So my question is: why did they not try and take the detonator or heavy weight off of Dyson? You can tell by the size of the building that they had no chance of getting out in time and he was in no state to resist them.

I understand they might not have been able to react fast enough to him dropping the weight, but it surely makes more sense to try and do something or at least try and talk him out of doing it. Instead they leave (slowly I might add) even when it's plain that they won't make it.