Add Fight.StopFight(); to anti-drown

//This is how I handle it in my very own fight mechanism:

_fightStartTs = DateTime.Now;
			// chase target if necessary, otherwise wait
			while (Conditions.InGameAndConnectedAndAliveAndProductStartedNotInPause && _target.IsAlive && _fightTrigger && !_target.IsTapDenied)
			{
				KeepTarget(_targetGuid);
				//MoveAwayFromEnemies(); // needs to know if enemy is caster
				KiteIfNecessary(_target);
				SwimUpForAir();
				PotionUser.UsePotions();
				ChaseTarget(_target, () => ClassRotation.Range);
				HandleEvade(_target);
				EscapeIfNecessary();
				Thread.Sleep(150);
			}

private static void SwimUpForAir()
		{
			if (AntiDrown.NeedsAirInCombat)
			{
				AntiDrown.GaspForAir();
			}
		}

using System;
using System.Collections.Generic;
using System.Threading;
using robotManager.FiniteStateMachine;
using SmartRobot.Bot.Helpers;
using wManager.Wow.Enums;
using wManager.Wow.Helpers;
using wManager.Wow.ObjectManager;

namespace SmartRobot.Bot.States
{
	public class AntiDrown : State
	{
		private static DateTime _breathExpires = DateTime.MaxValue;

		static AntiDrown()
		{
			EventsLuaWithArgs.OnEventsLuaStringWithArgs += AntiDrownEventHandler;
		}

		public override string DisplayName => "AntiDrown";

		private bool NeedsAir => DateTime.Now.AddSeconds(30) > _breathExpires;
		
		public static bool NeedsAirInCombat => DateTime.Now.AddSeconds(15) > _breathExpires;

		public static bool IsBreathing => _breathExpires != DateTime.MaxValue;

		public override bool NeedToRun => Conditions.InGameAndConnectedAndAliveAndProductStartedNotInPause
		                                  && ObjectManager.Me.IsSwimming
		                                  && NeedsAir;

		~AntiDrown()
		{
			EventsLuaWithArgs.OnEventsLuaStringWithArgs -= AntiDrownEventHandler;
		}

		private static void AntiDrownEventHandler(string id, List<string> args)
		{
			if ((id == "MIRROR_TIMER_START") & (args[0] == "BREATH"))
			{
				//sets BreathExpires to be in the future by x milliseconds
				var expiryDate = DateTime.Now.AddMilliseconds(double.Parse(args[1]));
				_breathExpires = expiryDate;

				if (!ObjectManager.Me.HaveBuff("Water Breathing"))
				{
					ItemsManager.UseItem(5996);
				}
			}

			if (id == "MIRROR_TIMER_STOP")
			{
				_breathExpires = DateTime.MaxValue;
			}
		}

		public override void Run()
		{
			GaspForAir();
		}

		public static void GaspForAir()
		{
			Logger.Info("Swimming up for air");
			MovementManager.StopMove();
			while (Conditions.InGameAndConnectedAndAliveAndProductStartedNotInPause && IsBreathing && ObjectManager.Me.IsSwimming)
			{
				Move.JumpOrAscend(Move.MoveAction.DownKey, 1000);
				Thread.Sleep(500);
			}

			// wait at surface
			while (Conditions.InGameAndConnectedAndAliveAndProductStartedNotInPause && IsBreathing && !Common.IsAttackedByNpc)
			{
				Thread.Sleep(500);
			}
		}
	}
}

Hope it helps for inspiration.