I guess everyone has their own scenarios or idea of what they may see or need in a SHTF situation
Example:
My thought is if your going down a busy Highway and encounter a active shooter/road rage incident or protest like we witnessed in the past years with traffic blocking and ripping people from their cars. No way out. No getting out of the vehicle etc
You could have a rifle in a case, passenger or rear seat, easy to reach where you could semi have it ready to go if needed.
Getting out and grabbing from the box. Especially if bagged up etc takes time. It also means you’re likely rolling with an uncased rifle into whatever situation lies ahead from that point on. If seen could trigger a reaction especially from LE if your seen loading up on the roadside
Again to each their own. Our patrol cars have them accessible from the drivers seat. Could literally shoot through the windshield if you absolutely needed without the need to stop the vehicle
I know some who carry handguns unloaded, locked in a box or glove compartment. Personally mine is on me or east to reach/loaded in the passenger compartment for the same reasons.
Rifle rides in the passenger compartment as well with the batteries on the red dot a flashlight checked often.
My idea of SHTF is immediately needing it. Carjacking/active shooter that you roll into/road rage type incidents. Otherwise you could simply stop, turn or otherwise try to avoid the situation altogether vs loading a rifle on the side of the road and driving into something you likely could have avoided
I have a pistol on my person and six magazines accessible in the cab of my truck. I also have a plate carrier behind my seat, a ballistic helmet behind my seat, and a pair of electronic earplugs in the center console. I also have a secondary [loaded] pistol [Colt Detective Special] with eight reloads.
The likelihood that I happen to be at the epicenter of a decisive "SHTF" event as it is unfolding, that requires immediate access to a rifle on 3 seconds notice or else I am going to die because the stuff I have at hand is insufficient to deal with the threat, is vanishingly small and in my calculation it does not justify the obvious risk of theft of keeping a rifle readily accessible and displayed in the cab. Furthermore, in the era of Karens, it is far more likely some busy-body will call police and make me the focus of police attention because "I saw a rifle in his truck!" Granted, I do have a rifle in my truck, but it is out of sight and while not immediately accessible it is also not immediately visible.
On one occasion I deemed it necessary, proper, appropriate, and prudent, and worth the possible risk, to have a rifle on my passenger seat and that was when I was on an interstate highway about to pass through a major metro area during the George Floyd "mostly peaceful protest" riots of summer 2020, at which time I placed the rifle on the seat, covered it with a jacket, and proceeded on my voyage. That was once in my entire life when I imagined the possibility of not only needing a carbine but needing it on 3 seconds notice. That was the only major road that would take me home at that time.
If I encounter a road rage incident, as long as I can drive, I am driving away, not my family not my problem. I don't have qualified immunity and nobody pays me, my legal fees, or my medical bills, and I can throw my life away intervening in somebody else's road rage incident with a pistol just as easily as with a rifle, in short, I am not intervening. Active shooter? I may or may not intervene depending on the circumstances. Protests? If I know about them in advance I will modify my route to avoid them.
The key words you said was "patrol cars." Your job entails having immediate access to a rifle, you have qualified immunity, and you are actively responding to situations that may require you to immediately use your rifle upon arriving at the scene. I am not driving around responding to requests, calls, or looking to intervene in such situations. While I have trained to fire a carbine from inside of the cab of a vehicle and how to deploy a carbine in and around a vehicle, my concerns are more "99% of situations will have this rifle stolen before I ever get to use it, or it will result in a Karen calling police, less than 1 in 100,000 situations will require me to need this immediately available" so I store my rifle so it is out of sight, even at the expense of time.
Also, if you're in a car and there is "no way out" because of protests on the highway, it suggests dozens of cars are in front of you and you have time. If there are no cars in front of you, then why did you stop? Honestly, I'm not stopping for a mob that decides to get in front of my truck, if I cannot navigate back or to the side, I am going forward.
In a perfect world I would be fine with a rifle being in the cab, immediately accessible, but we don't live in a perfect world, in my perspective all having a rifle stored visibly in the cab of my truck will do is make me a target for thieves, Karens, and cops, groups I simply don't want to interact with and whose radar I don't want to be on.
I agree in spirit, theoretically that is, that a rifle in a cab is ideal. If the world goes Mad Max tomorrow and the roads are still somewhat open and navigable, I will have a suppressed PDW rifle on my passenger seat, but unless and until that happens, I am not going to have a rifle openly visible in the cab of my truck.