That was a scheduled show the flag port call. There is no way a SSBN would operate in those areas on the map near Europe. With 7,500-mile ranged missiles there is no reason for her to be there.
There are both rear patrolling areas and forward patrolling areas. The reason for being in forward patrolling areas (as close to their targets in Russia as it's possible) is simple - it's time of flight. For example, if the target is Naval Base Gadjievo in Murmansk region (with 5-7 SSBNs and a number of attacking and special submarines) defended by S-400 (which can intercept incoming warheads slowed down to 4,8km/s approximately at the altitude of 20 km) and your Ohio launch four missiles (with, say, four REs each) from rear patrolling area, then they need say, forty minutes to reach their target. In forty minutes the Russians will be able to:
1) detect the launch and calculate trajectories - 1-2 min,
2) make a decision on Launch under attack (you know, Russians SSBNs can launch all their missiles in one salvo from the pier) 5-7 minutes ; and increase the readiness of S-400;
3) prepare submarines to the launch - 15 min;
4) actually launch 5*16 missiles with, say, 4 warheads each = 320 warheads against American cities - 3-4 min.
In sum - 24-38 min.
So, after all of this they still have time to smoke their last cigarettes or, if they are lucky, S-400 will intercept all 4*4=16 incoming warheads, they will reload their submarines and go to sea to fight another day (or even another week).
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But there is totally another situation if you launch from the forward patrolling area. With flight of time less then 10 min, they hardly will intercept few warheads, and other will transform their base in outpost of hell.
Of course, it works only with out of blue attack. If the Russians think, that there is a risk of uncontrollable escalation - they will just send their submarines and ships in sea long before becoming really provocative.
Anyway, of course, they must send their attacking submarines (at least one of them) to control that Ohio in forward patrolling area, and be ready to kill her at the very moment when she try to launch her missiles.
The position in the rear patrolling area is 'defensive' and a part of the Deterrence Type I. It is sending the message: 'If you attack our country and our nuclear forces, some submarines will survive anyway, and then, they will attack your cities or, at least, they will be tools of blackmail and negotiations for the better conditions of the peace. '
The position in the forward patrolling area is part of the Deterrence Type II, it's both aggressive and vulnerable.
It means: 'We can attack you if we consider your behavior extremely provocative (even if you don't) , but if you really want to continue the escalation (or can't retreat) you can gamble and have your chances in the preemptive strike'. You know, one of Pearl-Harbor scenarios.