Howcome fluid in inner ear causes impedance to sound while it travels faster in liquids than gases?

Now learn about impedance. If you hit a ball at the tip of the bat, speed is high but force is low. The ball is not accelerated much and the energy that is not transferred to the ball is reflected down the bat, stinging your hands and possibly breaking the bat. If you hit the ball near the end where you hold it, force is high but speed is low. The ball is not accelerated much, and the excess energy is reflected down the bat. If you hit the ball on the so called sweet spot, the ball gets maximum acceleration and no energy is reflected.

The ratio of high speed and low force is high impedance. The ratio of low speed and high force is low impedance. This concept applies to a lot of things. A guitar string is fixed (low impedance) at both ends, but one end works into a sound box which allows a high impedance so vibrations are transferred to air, which is a high impedance. An organ pipe might be closed (low impedance) at one end but it can be open (high impedance) at one or both ends and the combination determines its "voice".

Now you are talking about an eardrum, which is very thin skin, high impedance, so it gets the maximum energy transfer from air, which is also high impedance. Fluid is low impedance so the energy transfer is poor. The effect you describe is not because of impedance, it is because of mismatched impedance.