something popped into my mind that my grandfather liked to say was "ignorance is bliss"

as for jeff, no stamina needed except to enter, use the result button, no speedup for the result button needed. if you dont have the time to click on a tile and right after on the result button then i suggest to only play when you have 5-10 minutes to waste. no need to look at every individual battle to tweak your form because its always the same 2 battles. keeping an eye on your HP is no problem because it shows who is still alive and how much HP is left after everytime you clicked on the result button (hence the name "result", otherwise it would be a "skip" button that doesnt show the result).
if you can finish level 3 medium and kill the 1st bonus boss i suggest to jump to lv3 hard. the bonus bosses except for the 4th are easier than earthshatterer or whatever the 1st bosses name is from lv3 medium.
another suggestion: use khan and pent. with proper gear they can duo the entire lab and the other heroes are insignificant.
tips like this you will get from andys lab help post