How fast could Jakob run the 1500m if someone pulled a knife on him and started chasing him down the road?

Is the person chasing him on a bike??

Yes

For arguments sake, let's say it's Josh Kerr cycling towards him at current 1500m WR pace armed with a knife and slightly flat tyres

faster than Nordas 3.37 that’s for sure

Slower, he would sprint away ,going out too fast and once adrenaline wears off he slows down.

This is the answer. Probably 3:40-45.

He wouldn't make it a mile. I've watched enough horror movies to know that he would trip over his own feet repeatedly, keep stopping to bang on neighbors' doors when he got a decent lead, and would ultimately decide to hide in a woodshed where he would get a knife through his eye socket as he tries to peak outside through a small crack.

It’s an urban myth that people can summon significantly more muscle strength in life or death situations, the trite example of a mom being able to lift a car to save her child’s life.

Just doesn’t happen, though what does happen occasionally is ego lifters tearing a pec or bicep or tendon in the gym.

He’d safely drop him with a 48 400.