Yeah, it sounds like a stretch but leaving the "mission" intact might buy some time along with leaving the option for some nasty criminal charges.
Disable the bomb, let the plan move forward but keep train running a bit slower than usual. That sounds reasonable to me.
That commonly happens in train impacts.
People have accused train engineers for malfeasance during impacts in the past because the engine is heard to increase RPM's in an apparent attempt to INCREASE speed but the actual reason is because increasing power causes the front bogey to hunker down to prevent a derailment like this.