Underwater grapple

[Korwynne]

An underwater-breathing PC grapples a high-level NPC in the ocean. In my game, I've allowed a 3rd dimension to the water (in that this PC can drag the grappled creature 'down' as a move action).

I have a couple questions, and would appreciate your thoughts:

1) There are no rules in RAW about swimming vertically 'down'. The player really wants to drag enemies as far down as he can while maintaining the grapple. The thought would be that he has swim speed, and it would make for a lot more efficient drowning if the bad guy takes more than 1 round to get to the surface. I am employing max depth rules- in the latest situation, he'd bottom out at 50' of water. For the swim ability (without a swim speed), the rules identify that you can move at 1/4 speed as a standard move action. I'd argue that a player should be able to swim 'up' faster than this (allowing the drownee to surface from a 50' depth in 2 to 3 rounds instead of 6 to 10 rounds). Is that a reasonable approach?

2) Per the rules on moving a creature while grappled:
"If you attempt to place your foe in a hazardous location, such as in a wall of fire or over a pit, the target receives a free attempt to break your grapple with a +4 bonus." Is underwater (threat of drowning) a hazardous location? Would the opposing creature then get -2 (dex mod) and a +4 (hazardous modifier) every round? These would both apply to the escape artist check?

3) Are there penalties to attempting to grapple/maintain grapples underwater? What about if this became a pin attempt?

Thanks!

[Tarantula]

RAW: 1) You can't swim up faster than you can swim down or sideways. Its 1/4 movement any direction.

2) I'd rule that they get the +4 instant break check if he brought them into the water from outside the water, and/or underwater from the surface. Further checks to bring them further down would not give free escape attempts.

3) The only listed penalty for underwater grapple is: "A creature without freedom of movement effects or a swim speed makes grapple checks underwater at a –2 penalty, but deals damage normally when grappling."

So the thing he is grappling would be at -2 for no swim speed on its grapple escape attempts (unless using escape artist). The PC with a swim speed would not have any penalty (even for pin).

[Korwynne]

Thanks! Looks like I was overthinking it again - this is helpful!

[Lincoln Hills]

The same sort of action can be undertaken faster with a different combat maneuver (Drag or Reposition, both in the APG), but I presume your character has some specific reason to opt for grappling (such as having a related feat.)