consider this DS change

The double time is kinda insane. Honestly as it stands its one of the strongest perks in the game. If you want to remove the 60 second timer or give two uses, I think there would NEED to be a notification that you have it. Either change would be kinda insane without a major form of balancing.

The 10 seconds is out of the question, thats just way too substantial of a stun to be implemented.

Two uses is very strong, the killer would know after the first one, but there would need to be some kind of balancing feature, like putting the user into mend state or something of the sort.

For no time limit there needs to be a counter, like being unable to be used from a locker or the like so it can no longer be used offensively

I don't want to say its okay where it is, because it does need a nerf if anything (only because it is being used offensively), but I can't say that a buff is in order.

My personal problem with it being used offensively is as follows:

When someone uses their exhaustion and a number of strong loop positions to waste time, they are fulfilling their job as a runner, buying time for gens to be worked on. It takes 2 damage states to down, plus an exhaustion perk in most cases. If you hook this person and someone with bt bombs the hook, you have two options. You either tunnel, knowing full well they likely have bt and dstrike, or you go for the unhooker. The injured person will often body block, forcing your choice. So you must now get through the bt, which they will use to get to a locker, forcing you to either proc their dstrike, restarting the entire chase set, or force you to leave them in the locker to go apply pressure. They have used their perks offensively, to force you as a killer into a position where all of your map presence is made worthless. This is incredibly common at the high ranks, and if you don't spread damage early as you apply pressure, you are really shooting yourself in the foot

I don't know about the numbers there, but something in this sort of direction is probably how it would get changed if it gets changed.

Deactivation conditions/nerf to its potential "aggressive" use, buff to its anti-tunneling use. I think if it can't be waited out in any way during a chase or on the ground there's not really any need to make the stun any longer, if you want to encourage the actually tunneled survivor to try to get away from the killer it could keep its current stun time but give 5-10 seconds of no injury sounds + scratchmarks or something like that instead.

In my opinion even without those two buffs I wouldn't call your idea a nerf at least, it's a rework. From a more generalist perk to an actually specialized anti-tunneling perk that can't be "circumvented" by a killer that is legitimately tunneling someone, but also can't be "weaponized" by someone who isn't being tunneled at all.