Yeah the jetpack wouldn't propel the Mercenary that high in the air. Its main goal is to get you away from enemies that are trying to lock you down. Flying 30 feet up in the air is something I think they could leave for the movies ;D I imagine it not being any higher than when we use death from above.
/signed. so long as its not too easy for them to get out of the pits or over a voidstar wall, etc. that said, thatd be some sweet, well deserved utility.