The reason why this cost is going to force the optimal algorithm to explore the entire state space is the fact that large negative costs can cause concurrent automatically for optimal solutions.
<h3>The step to take with a negative cost</h3>
Now if there is the existence of a large negative cost for each of these actions, the optimal algorithm is going to try an exploration of the whole space state.
The reason for this would be the fact that the route that has the least consequences would be better of.
No. If you have your eyes fixed on one spot ahead of you - what happens when that spot moves over into the right lane (or something else) and you end up "following" it and there is a car to the right of you. You will end up in a collision.