Not sure how well it is modeled in the sim, but in theory, the deeper you go, the better your chances of survival usually are, for two reasons: first, there is a longer transit time for the depth charges, so you have more time to take evasive action; second, a depth charge has to be closer to an object to be effective in direct relation to how deep it goes, in order for the blast to overcome the increasing water pressure.
But there is a caveat to all that. If a depth charge does manage to go off close to your sub when you are deep, it will cause more damage, as the increased water pressure deflects more of the blast toward your submarine. This is the principle the Upkeep Mine used (or Bouncing bomb if you prefer the more popular name) when it was utilised to attack the German dams in WW2. So all that stuff you see in war movies where depth charges clatter down the side of a sub's hull before going off five feet underneath the thing, and all it does is spray a bit of water on the crew before they shut a valve off is probably complete crap, as something like that would almost certainly crack the pressure hull.
Having been fortunate enough to have been taken on an interior tour of U-534 (The Type IX German sub which was raised from the Skageraak), before it was closed to the public, I can report that the damage from the pressure wave of the detonating depth bomb dropped from a Liberator which sank it, was staggering; it had split the hull in the rear over about four to five feet, bending the plates inwards, and the pressure from this had also completely squashed one of the pipes running along the overhead nearby, literally like someone standing on an empty beer can.
The Japanese initially thought that US submarines could not go as deep as they could in actuality, and for the early part of the war, they generally set their depth charges to go off way to shallow, and US submarines were generally very robust too, meaning they could often go a lot deeper than the specs suggested. Later in the war the Japanese realised the error of their tactics and started blasting things a lot deeper.
Chock