You could use it for a gunlock, if you tapped into the horn, or horn ring circuit you could set a timed input for so many seconds which you could activate another mode on the lightbar and/or mode on lights for a different pattern to help clear intersections.
I use a timed input as a shut down timer. I like using the 4200 this way over something like a ChargeGuard because if it fails the equipment attached to it will still turn on with the ignition and is way cheaper than a ChargeGuard because you just need a relay. You have to make sure though your ignition source can handle the load if you use the timer circuit for anything other than the 4200.
I am trying to set up a timer so my 4200 controller stays on for 10 mins after i shut off the ignition, but it does not seem to work properly. the head goes off when i turn off the ignition. the head will stay on only if i have a button activated.