The original 1966 score of "Mission impossible" was written entirely in 5/4 time (you can listen to it here).
For the first movie staring Tom Cruise, the theme was rewritten by two U2 band members, and after the initial theme (still in 5/4) it changes it time signature to 4/4, you can listen to it here.
Now I am listening this cover version of Paolo Sereno as played by Sungha Jung. And here the intro is also in 5/4, but when the melody starts (around 16s, see this link) he also seems to switch the time signature, but it does not seem to be 4/4, I guess its 6/4 but I am not sure? So can you hear what time signature he plays when the melody starts in?