What were the people complaining about this time?
Rashi: They were complaining that everybody was allowed to enter (the Azarah of) the Ohel Mo'ed, but if someone went a fraction closer than his friends, he was Chayav Misah. 1
Rashbam: They were complaining that, bearing in mind that they were permitted to enter the Mishkan at will, 2 it was difficult to escape the urge to guard it or to assist the Levi'im in their Avodah, which would result in their death.
Rashi: Something that it is all but impossible to adhere to.
Rashbam: Since the prohibitions in Vayikra 21:17 and 22:3 refer only to a Ba'al-Mum and serving be'Tum'ah.
What did they mean when they added "ha'Im Tamnu Ligvo'a"?
Rashi: They meant 'Are we Hefker to die'?
Rashi #2 (in Eichah, 3:22): They meant 'Are we finished to die?'